Smallest structural unit of a multicellular organism
What does the endoplasmic reticulum consist of?
a network of tubules bounded by membranes
What is the cell composed of?
-surrounded by cell membrane
- composed of a nucleus and cytoplasm that contains organelle and inclusions.
- cellular shape, size and structure vary widely according to its function
What is the difference between rough ER and smooth ER?
Rough ER is covered in ribosomes while smooth ER is not
What is the cytoplasm?
Fluid between the nucleus and membrane
Aggregates of the rough ER appear as what?
live material that have a definite function within the cytoplasm of the cell
What is the rough ER involved in?
How wide is the cellular membrane?
8 to 10mm
What is the smooth ER involved in?
lipid metabolism and synthesis of steroid hormones
Smooth ER is involved in...
Drug detoxification, release and recapture of calcium ion during contraction and relaxation of muscles
What does the cellular membrane look like at the E/M level
it's trilaminar and consists of an outer and inner electron dense lamina and a electron-lucent intermediate lamina
What is the function of the golgi complex?
Provides a site for the accumulation, concentration, and packaging of secretory proteins into membrane bound vesicles, and the biosynthesis of glycoprotiens, glycolipids, phospholipids, and neutral lipids
Functions of the golgi complex
1) Provides site for the accumulation, concentration and packaging of secretory proteins into membrane bound vesicles.
2) Biosynthesis of glycoproteins, glycolipids, phospholipids and neutral lipids
What does the cell membrane consist of?
2 leaflets of phospholipid molecules
integral and peripheral proteins
glycocolax coat present in the outer membrane.
What are lysosomes
membrane-bound vesicles that contain various hydrolysis enzymes
membrane-bounded vesicles that contain various hydrolytic enzymes
Membrane bound vesicle that contains various hydrolytic enzymes (ex. nuclease, lipase, etc)
What is the function of the glycocalyx coat?
protects the cell from mechanical and chemical damage, found in the outer layer
Where are lysosomal enzymes synthesized
in the rough ER
What are the functions of the cell membrane?
2.special receptor site for antigen recognition and immunological mechanisms
3. special receptor sites for hormones
What is the function of the cell membrane?
Selectively permeable (transport). Special receptor sites for antigen (foreign body) recognition and immunological mechanisms (phagocytosis). Special receptors for hormone activated cellular events
What are primary lysosomes?
they are packaged in the golgi complex with modified hydrolytic enzymes synthesized in the rough ER
Buds off the golgi complex
What makes up the nucleus?
bounded by a nuclear envelope and contains chromatin, nucleolus or nucleoli and a nuclear matrix
Chromatin, nucleolus or nucleoli and a nuclear matrix
What does the nucleus contain?
Chromatin, nucleoli, and a nuclear matrix
What are secondary lysosomes
when the primary lysosomes fuse with phagocytosed material or obsolete cellular oragnelles
What happens to secondary lysosomes?
after digestion their contents are retained as residual bodies or lipofuscin
Fusion of a primary lysosome with the phagocytksed material or obsolete cellular organelles
What shape does the nucleus usually take?
most nuclei are spherical or ovoid, but may be spindle-shaped (smooth muscle), bean or kidney shaped ( monocytes) or multiobulated (neutrophil leucocytes)
What cells have more than one nucleus?
skeletal muscles cells and osteoclasts
What cells lack nuclei?
Mammalian erythrocytes lack nuclei
What does the nuclear envelope consist of?
two concentric membranes separated by a 25-mm wide perinuclear space
Nuclear envelope consists of...
Two concentric membranes
What are are attached to the outer nuclear membrane?
it is studded with ribosomes and is continuous with rough endoplasmic reticulum
What are peroxisomes
small membrane bounded organelles contain oxidase and catalase enzymes which synthesize and destroy hydrogen peroxide
oxidase and catalase enzymes
What are peroxisomes?
Small membrane bound organelles that contain oxidase and catalase enzymes, which synthesize and destroy hydrogen peroxide. Detoxify certain substances (ethanol) and play a role in gluconeogenesis
What are the characteristics of the inner nuclear membrane?
membrane proteins and specific sites of chromatin (hetero) are attached.
Where are peroxisomes most abundant
in hepatocytes and cells of the proximal convuluted tubules of the kidney
Peroxisomes are abundant in...
Heptaocytes and cells of the proximal convoluted tubules of the kidney
What is mitochondria
chief sources of energy in the cell (ATP synthesis)
Chief source of energy. Composed of an inner and outer membrane. Inner membrane has cristae (folds) which contain enzymes that function in oxidative phosphorylation. Matrix contains DNa and ribosomes
What is the nuclear envelope interrupted by?
numerous pores which provide selective and active transport between nucleus and cytoplasm
How many membranes does mitochondria have?
2 an outer and inner membrane
What does the inner membrane of the mitchondria contain
enzymes involved in oxidative phosphorylation
What does the mitochondrial matrix contain?
DNA and ribosomes
What is chromatin composed of?
DNA, basic proteins, histones and nonhistone chromosomal proteins
Chromatin is composed of...
deoxyribonucleic acid (DNA), basic proteins, histones and nonhistone chromosomal proteins
What are the two types of chromatin?
found in basophilic clumps, predominate in relatively inactive cells
3 things the cytoskeleton is composed of
microfilaments, microtubules, and intermediate filaments
particularly abundant in active cells, lightly stained and uniformly dispersed
What are microfilaments
important in exo/endocytosis and cell migratory activity, mainly composed of actin and myosin filaments
Mainly composed of actin and myosin. Cause muscle contraction. Associated with endocytosis, exocytosis, and cell migratory activity
What is a sex chromatin called and where is it found?
Barr Body, multiobulated.
prominent in neutrophils in females
What are intermediate filaments?
they give the cell its structure
Where are intermediate filaments found?
All cells but abundant in those subject to mechanical stress
What kind of cells are intermediate filaments found in?
In cells under mechanical stress
What is the nulecolus?
a spherical and basophilic structure, prominent in cells that are actively synthesizing.
composed of loops of DNA which contain ribosomal RNA (rRNA)
What are microtubules
tubular structure that allow the organelles and vesicles to move within the cell, they are also involved in cell division
Maintain cell form and transport organelles and vesicles. Also play a role in cell division and comprise the centriole
What part of cell division do microtubules play an important role in
they are major components of the centriole
What is the centriole composed of?
nine groups of 3 microtubules in longitudinal and parallel arrangement
List the 5 cytoplasmic Inclusions
What does the nucleolus do?
rRNA synthesis and its packaging into precursors of RNA
What is the nucleolus?
Spherical and basophilic structure, prominent in cells that are actively synthesizing protein. Composed of loops of DNA containing rRNA genes. Involved in rRNA synthesis and its packaging into ribosome precursors
what is lipofuscin?
indigestible residue of phagocytosis commonly found in cardiac muscle, liver and nerve cells. This pigment increases with age!
What is lipofuscin?
What is lipofuscin?
Age pigment. Contents of the secondary lysosome that are retained as residual bodies
What is hemosiderin?
results in hemoglobin degredation
Result of hemoglobin degradation
What are ribosomes?
small electron dense cytoplasmic particles (15-25nm in diameter)
Where are ribosomes found?
Freely in the cytoplasm or with rough ER
What is melanin?
gives skin and retina its pigment
In skin and pigment epithelium of retina
what is a cytoplasmic inclusion lipid?
its in adipose cells and can be demonstrated with osmic acid fixation
What is glycogen in relation to cytoplasmic inclusion
found in liver cells and muscle, can be demonstrated by PAS reaction
Where do ribosomes occur and where are they found?
occur either singly or in groups, called polyribosomes or polysomes. occur freely in the cytoplasm or in the rough ER
found in all cells except mature mammalian erythrocytes.
What is the function of a ribosome?
What is a tight juction?
found in epithelial cells and consist of irregular transmembrane proteins that seal neighboring cells together like a belt
What do tight juctions prevent?
the passage of water soluble molecules from the lumen to intracellular space and vice versa
What are the 3 tyoes of Adhering (anchoring) Junctions?
Desmosomes (Macula adherens)
Explain Zonula adherens junctions
cells are held together by transmembrane proetien linker and a bundle of actin filaments (found in the lining of the intestines)
Explain Desmosome junctions?
transmembrane protein linker and intercellular electron dense plaque hold cells together, Intermediate filaments are attracted to the plaque and they form a hairpin loop
they connect the cells from the extracellular matrix protein (like half the desmosome)
What do Communicating (Gap juctions) permit through the junction
they oermit the direct passage of inorganic ions and other water soluble molecules from cell to cell
How are gap junctions connected
the intercellular space is bridged by interlocking transmembrane protiens of the apposed membrane
What are cillia
allow the movement of mucous and sperm/oocytes, composed of 9 doublet microtubules around 2 central microtubules
What is a flagellum
single long cillium (sperm)
Single, long cilium. Example = spermatozoon
what are microvilli
fold of the cytoplasm (cytoplasmic evagination) to increase the free surface for absorption (small intestine digested food absorption)
Cytoplasmic envaginations that increase surface area for absorption, like in the small intestines
What is a brush border
lots of microvilli (look like bristles of a brush)
What are Stereocilia
long rigid microvilli (hair cells of the spiral organ of the inner ear)
Stereocilia are found in...
hair cells of the spiral organ (corti) of the inner ear
Long, rigid microvilli. Example = inner ear
Width of Cell membrane
Like H2O and face both the cytoplasmic and extracellular surface
Hates H2O, tails oppose each other
Proteins associated with the lipid bilayer
Integral transmembrane protein and peripheral membrane protein
Glycocalyx consists of...
Glycolipid and glycoprotein
Purpose of the glycocalyx coat
Protects the cell from the mechanical and chemical damage
Nuclear envelope bounds what?
Spindle-shaped nuclei are found in what type of muscle?
Bean or kidney shaped nuclei are found in...
multilobulated nuclei are found in...
What cells contain several nuclei?
Skeletal muscle cells and osteoclasts
What lacks nuclei except chickens?
The perinuclear space is how wide?
2 forms of chromatin
Heterochromatin and Euchromatin
In basophilic clumps, predominant in relatively inactive cells
particularly abundant in active cells, lightly stained and uniformly dispersed
Nucleolus is prominent in cells that are...
actively synthesizing protein
Nucleolus is involved in...
Synthesis of rRNA and its packaging into precursor of ribosomes
Ribosomes have a diameter of about...
Group of ribosomes
Another name for polyribosomes
2 places ribosomes occur
Freely in the cytoplasm and in the rough ER
What cells do NOT contain ribosomes?
2 types of Endoplasmic reticulum are...
Rough ER and Smooth ER
Basophilic and are involved in protein synthesis
Abundant in cells involved in lipid metabolism (synthesis of steroid hormones). Also involved in drug detoxification and release and recapture of calcium ion during muscle contraction/relaxation
Aggregates of rough ER appear as _______ and are involved in _______ _______.
basophilic; protein synthesis
Smooth ER is abundant in cells involved in...
lipid metabolism (synthesis of steroid hormones)
The golgi complex can be stained with what?
Silver salt or osmium
How does the golgi complex appear after staining?
Black network of cisternae
Examples of hydrolytic enzymes
nucleases, proteases, lipases
cell degradation of unnecessary or dysfunctional cellular components through the actions of lysosomes
Contents of the secondary lysosomes are retained as...
residual bodies or lipofuscin
What cells are lipofuscin (age pigment) found in?
Long lasting cells like...liver, nerve, cardiac
Oxidase and catalase enzymes do what?
Synthesize and destroy hydrogen peroxide
Peroxisomes detoxify certain substances like _____ and play a role in _______.
Mitochondria are the ____ for the cell.
chief source of energy
Mitochondria will be stained with what?
Janus Green B
Mitochondria is the only organelle, outside the nucleus, to have...
DNA and ribosomes
Microfilaments are composed of...
Actin and myosin filaments
Actin and myosin filaments cause...
contraction in muscle cells
Microfilaments are associated with membrane activities such as...
endocytosis, exocytosis and cell migratory activity
Intermediate filaments are present in...
Almost all cells - abundant in cells subject to mechanical stress
Keratin filaments provide mechanical ____ by formation of ______.
Another name for keratin filaments
Desmin filaments support...
Glial filaments support...
astrocytes and neurolemmocytes
Another name for neurolemmocytes
Also called Schwann cells. Produce myelin sheaths around axons in PNS. The sheath is interrupted by by uninsulated sites called Nodes of Ranvier
Microtubules play a significant role in...
maintenance of cell form and transport of organelles and vesicles, such as secretory granules
Microtubules play an essential role in ___ ____ and are the major component of the _____.
cell division; centriole
Centriole is comprised of...
9 groups of 3 microtubules (triplets) in a longitudinal and parallel arrangement.
What are the 9 groups of 3 microtubules called?
In liver cell and muscle, can be demonstrated by PAS reaction
In adipose cells, can be demonstrated with osmic acid fixation
Tight junctions are found in...
Found in epithelial cells. Seals neighboring cells in a belt-like fashion, in which water soluble molecule cannot be passed from the lumen to the interstitial space
Tight junctions consist of...
Irregularly anastamosing ridges that seal neighboring cells together in a belt-like fashion.
Tight junctions constitutes a barrier that prevents the passage of _____ _____ molecules from the _____ to _______ ______ and vice versa.
water soluble; lumen; intercellular space
Types of adhering junctions
1) Zonula adherens
2) Desmosomes or Macula adherens
Zonula adherents are held together by...
transmembrane protein linker and a bundle of actin filaments
Zonula adherents are prominent in the lining cells of the ______.
transmembrane protein linker plus intercellular electron-dense plaque
______ filaments are attached to desmosomes forming a _____ ____.
Intermediate; hairpin loop
cells from extracellular matrix protein.
What is stronger desmosomes or hemidesmosomes?
Communicating (gap) junction permit...
direct passage of inorganic ions and other water-soluble molecules from cell to cell
In a gap junction how is the intercellular space bridged?
By interlocking transmembrane proteins of the apposed membrane
Cilia are found where?
Respiratory system and male and female system (movement of mucus or spermatozoa or oocytes)
Composed of nine doublet microtubules around two central microtubules. Seen in respiratory and genital tracts
What is a single long cilium referred to as?
These are cytoplasmic evagination to increase the free surface for absorption
Microvilli are commonly found where?
Long, rigid microvilli are called...
consists of sheets of aggregated cells of similar type that cover or line the external and internal surfaces of the body
Epithelium resting on the basement membrane can be demonstrated with...
PAS technique or silver salt staining
Basement membrane consists of...
1) Lamina lucida
2) Lamina densa
3) Subbasal lamina
What does the basement membrane consist of?
Lamina lucida (next to epithelium), Lamina densa (electron-dense), Subbasal lamina (composed of reticular fibers connecting lamina densa to CT)
What makes up the basal lamina?
1) Lamina lucida
2) Lamina densa
What is the lamina lucida?
A low density, clear area next to the epithelium
What is the lamina densa?
An electron dense layer composed mainly of proteoglycans and a special type of collagen
What is the subbasal lamina composed of?
What does the subbasal lamina connect?
The lamina dense to the sub epithelial connective tissue
What are the functions of the basement membrane
Protection, absorption, secretion, and diffusion
Classification of epithelium is based on...
1) Number of layers present
2) Shape of the cells
single layer of cells resting on the basement membrane
two or more layers of cells with only the basal cell layer resting on the basement membrane
What are the 3 shapes of epithelium?
Simple squamous epithelium
a single layer of thin, flat and scale-like cells with a spherical or oval nucleus giving a bulging appearance
Simple squamous epithelium are found...
lining of the blood vessels, pleural and peritoneal cavities, pulmonary alveoli and glomerular capsule
Simple squamous epithelium
Single layer of thin, flat, scale-like cells. Spherical/oval nucleus. Example = lining of blood vessels, pleural/peritoneal cavities
Simple cuboidal epithelium
Single layer of cuboidal cells with centrally placed nucleus
Simple cuboidal epithelium are found...
In thyroid gland, collecting ducts of the kidney
Simple cuboidal epithelium
A single layer of cuboidal cells with centrally placed nucleus. Example = thyroid gland, collecting ducts of the kidney
Simple columnar epithelium
Tall, narrow cells with an oval nucleus located near the base of the cell
Simple columnar epithelium
Tall, narrow cells with an oval nucleus located near the base of the cell. Example = stomach, intestines, gall bladder
Simple columnar epithelium cells are found...
In stomach, intestine and gall bladder
Pseudostratified columnar epithelium
Single layer of cells, but different cell shapes and position of nuclei gives impression of stratified epithelium
Pseudostratified columnar epithelium are found...
In trachea and bronchi (ciliated form)
Pseudostratified columnar epithelium
Single layer of cells but different cell shape/nucleus location makes it appear stratified. Example = trachea and bronchi (ciliated)
Stratified squamous epithelium
Several layers of cells with the top most layer having a squamous shape
Where is stratified squamous epithelium found?
Skin (keratinized) and cornea (non-keratinized)
Stratified squamous epithelium cells are found...
In skin (keratinized) and cornea (non-keratinized)
Stratified cuboidal epithelium
Several layers of cells with the top most having the cubodial shape. NEVER more than 3 layers
Where is stratified cuboidal epithelium found?
Lining of the excretory duct of glands
Stratified cuboidal epithelium cells are found...
In the lining of excretory ducts of glands
Stratified columnar epithelium
Several layers of cells with the top most layer having the columnar shape. 3-4 layers
Where is stratified columnar epithelium found?
Parotid and mandibular gland ducts
Stratified columnar epithelium cells are found...
in parotid and mandibular gland ducts
Line certain hollow organs and is capable of considerable distention
Lines certain hollow organs and is capable of distension, like the urinary bladder. When relaxed, superficial cells are dome-shaped and bugle into the lumen. When stretched, it is reduced to a few layers of flattened cells
Transitional epithelium cells are found...
In urinary bladder and urethra
Transitional epithelium cells in a relaxed state...
are dome-shaped and bulge into the lumen
Transitional epithelium cells when stretched...
are reduced to only a few layers of flattened cells
consists of glandular or secretory epithelium and duct system (parenchyma) with a supportive framework of connective tissue (stroma)
What is a gland?
Consists of glandular or secretory epithelium and duct system (parenchyma) with a supportive framework of CT (stroma)
ductless gland, secretions are released into intercellular fluid and transported to site of action by blood
with a system of ducts, uses the ducts to transport secretions to action site
proteoglycans, glycosaminoglycans and interstitial fluid
What is amorphous ground substance composed of?
Glycosaminoglycans (GAGs) and proteoglycans
Irregularly shaped with multiple processes, usually found adjacent to blood vessels
Serve as a reservoir of cells that can differentiate into any other type of CT. Usually found adjacent to blood vessels
Mesenchymal cells serve as...
a reservoir of cells that can differentiate into any other type of connective tissue cell
Most common cells and responsible for synthesis of fibers and intercellular ground substance (wound repair)
2 stages of activity
1) Fibroblast (active)
2) Fibrocyte (quiescent)
The active fibroblast has/is...
1) long and branched cytoplasm processes
2) ovoid nucleus
4) cytoplasm is rich in rough ER and golgi complex
Contain actin filament
Fibroblasts that contain actin filaments. Play a role in contraction during wound repair
Myofibroblast play role in...
contraction during wound healing
Stellate-shaped cells with spherical nucleus and basophilic cytoplasm
Stellate shaped cells with spherical nuclei and basophilic cytoplasm. Produce reticular fibers
Reticular cells produce...
adipose or fat cells
Unilocular filled with large lipid droplets and have peripherally displaced nucleus. Multilocular (brown fat) have centrally located nucleus with multiple lipid droplets and high concentration of mitochondria in cytoplasm
2 types of adipocytes
Filled with large lipid droplets; nucleus is displaced to periphery
Unilocular adipocytes are also known as...
centrally located nucleus, multiple lipid droplets and high concentration of mitochondria
Another name for multilocular adipocytes
Elongated cells located adjacent to the endothelium lining small blood vessels
actin and myosin
Elongated cells adjacent to endothelium lining small blood vessels. Contain actin and myosin, can transform into other cells, and participates in healing process
Pericytes have the potential to...
transform into other cells and participate in healing process
Mast cells are common where?
Loose connective tissue and abundant around blood vessels
What are mast cells?
Large polymorphic, spherical or ovoid cells, which contain numerous secretory granules in the cytoplasm
Produce heparin and histamine. Large, spherical cells common in loose CT and around blood vessels. When stained with toluidine blue, numerous granules in cytoplasm stain red
With what are mast cells stained? What color do they turn?
Stained with toluidine blue. Stain red (metachromatic stain)
Mast cells produce...
heparin (anticoagulant) and histamine (vasoconstrictor)
What is heparin?
What is histamine?
Plasma cells are...
Spherical or ovoid cells with spherical, eccentric nucleus
Round cell with spherical, eccentric nucleus and very basophilic cytoplasm. Arrangement of chromatin give a cartwheel like appearance. Develop from B lymphocytes and produce antibodies
The arrangement of chromatin give plasma cell nucleus a...
The cytoplasm in plasma cells is intensely...
Plasma cells are abundant in...
lymphatic tissues and lamina propria of the GI tract
Plasma cells develop from ______ and produce ________.
Macrophage cells derived from...
monocytes that migrate across the blood vessel walls to connective tissue
Phagocytic cells, large, ovoid or spherical cells that contain cytoplasmic vacuoles and numerous lysosomes
Phagocytic cells derived from monocytes. Large, spherical cells that contain cytoplasmic vacuoles and numerous lysosomes
cells containing pigments
What is the pigment in pigment cells
Cells containing melanin (ex. dermis, iris)
What are examples of pigment cells
dermis, uterine caruncles, choroid and iris
lymphocytes, monocytes and granulocytes (blood cells) that migrate through the wall of the capillaries to the connective tissues
What are the 3 connective tissue fibers?
Collagen, Reticular and Elastic fibers
Where are collagen fibers present?
In tendon, ligament and organ capsule
What fibers are most abundant in mature connective tissue?
Collagen fibers are composed of what fibrous protein?
Collagen fibers are strong and flexible but ____.
Collagen fibers have what type of arrangement?
What stain is used to stain collagen fibers red? Blue?
Red: Van Gieson's Method
Blue: Mallory's and Masson's Trichrome
Reticular fibers form delicate, _____ networks.
Reticular fibers form networks around...
Capillaries, muscle fibers and nerves
Reticular fibers form the framework of...
Live, endocrine and lymphatic organs
Reticular fibers can be stained with...
Silver impregnation OR PAS reagent
What is used to stain reticular fibers?
Argyrophilic or argentaffin stain (silver impregnation), and PAS reagent
Reticular fibers are also called _____ because of their affinity for sliver salts.
Reticular fibers are actually individual collagen fibrils or?
Type 3 collagen
Type 3 collagen is coated with...
proteoglycans and glycoproteins
What fibers are present in structures that require elasticity?
Where are elastic fibers found?
Aorta and muscular arteries, nuchal ligament, Pinna of ear and lungs
Where are elastic fibers found?
Arteries, nuchal ligament, pinna of ear, lungs
Elastic fibers are stained light pink in what stain?
Elastic fibers are selectively stained by what 2 stains?
Orcein and resorcin-fuchsin
Elastic fibers are composed of ____ _____, covered by _____.
elastin protein; glycoprotein
What is a glycoprotein that is essential for formation of elastic fibers?
5 major types of GAGs
1) Hyaluronic acid
2) Chondroitin sulphate
3) Dermatin sulphate
4) Keratin sulphate
5) Heparin sulphate
Where is hyaluronic acid found?
vitreous body of eye and in synovial fluid
GAG found in vitreous body of eye and in synovial fluid
Where is chondroitin sulphate found?
Cartilage, bone, and large blood vessels
Where is derma tin sulphate found?
Tendons and ligaments
Where is keratin sulphate found?
Cartilage and bones
GAG found in cartilage and bone
Where is heparin sulphate found?
Arteries and lungs
GAG found in arteries and lungs
How are proteoglycans formed?
Covalently linking GAGs to a protein core
What are the 2 types of Embryonic CT?
Mesenchymal and Mucous or gelatinous CT
What are mesenchymal CT composed of?
mesenchymal cells and fluid-like ground substance
Mesenchyme CT gives rise to...
various types of adult connective tissue
Mucous (gelationous) CT is found...
In umbilical cord and bovine glans penis
Mucous (gelationous) CT is composed of...
fibroblast, gel-like ground substance and collagen fibers
What are the 5 Adult CT?
1) Loose or Areolar CT
2) Dense CT
3) Elastic CT
4) Reticular CT
5) Adipose CT
Loose (areolar) CT is found...
Beneath epithelium, around blood vessels and nerves, and in serous membranes
Loose (areolar) CT form a loose network of..
collagenous, reticular and elastic fibers
Dense CT is mainly composed of...
thick collagenous fibers and few fibroblast cells
2 types of dense CT
Irregular and regular
Dense irregular CT is in...
capsules of organs, deep layer of dermis
Dense regular CT is in...
tendons, ligaments and aponeurosis
Elastic tissue is characterised by...
numerous regularly or irregularly arranged elastic fibers
Also called gliocytes. Provide structural and functional support
What's the structure and function of astrocytes?
Star shaped cells that contain glial filaments. Provide structural support by binding neurons to capillaries and to the pia mater. Terminate in "end feet" which helps maintain electrolyte balance in CNS
In white matter. Processes are long, slender, and moderately branched
In grey matter. Processes are short and highly branched
Produce myelin sheath in CNS, which provides electrical insulation for neurons
Ciliated cuboidal or columnar cells that line the ventricles of the brain and central canal of the spinal chord (CNS). Facilitates movement of cerebrospinal fluid
What are the layers of CT of the PNS?
Endoneurium, Perineurium, epineurium
Associated with cranial ganglia or spinal ganglia. Contain cell bodies of unipolar neurons. Each cell body is tightly encapsulated by satellite cells
Accumulations of multipolar neurons along the course of autonomic nerves
Types of nonencapsulated receptors
Free nerve ending, tactile corpuscles
Types of encapsulated receptors
Meissner's, Paccinian, Krause's, neurotendinous and neuromuscular spindles
What neurotransmitter leads to muscle fiber depolarization?
What is the grey matter of CNS?
Nerve cell bodies. Ventral have efferent neurons, dorsal have interneurons
What is the white matter of the CNS?
Processes. Dorsal, ventral, and lateral funiculi. Ascending and descending tracts
What are the six layers, superficial to deep, of the cerebral cortex?
Sexual behavior by detection of odor of opposite sex
Pseudostratified ciliated columnar epithelium with goblet cells.
Stratified squamous non-keratinized epithelium. Gradually changes to typical respiratory epithelium (ciliated pseudostratified columnar) caudal to the vocal fold
Lined with pseudostratified ciliated columnar epithelium with goblet cells. Neuroendocrine cells are abundant in young animals (amine precursor uptake). C or U shaped hyaline cartilage, external in carnivores and internal in domestic animals
In which species is the pleura of the lungs thickest? Thinnest?
Thickest in ruminants, thinnest in dog/cat
Epithelium of pleura of the lungs
Simple squamous epithelium
Pseudostratified ciliated columnar epithelium with goblet cells. Proximodistally, epithelial height and goblet cells decrease and Clara cells (exocrine gland) increase. Proximodistally cartilage decreases and smooth muscle increases
Simple columnar or cuboidal epithelium with Clara cells. Cartilage and glands are absent
Transition zone that is the center of most lung disorders. In carnivores, they're extensive. In horse, cow, and pig, they're short or absent
Alveolar duct and alveolar sac
Alveolar duct arises from respiratory bronchioles and terminates in clusters of alveoli called alveolar sacs. Simple cuboidal or squamous epithelium
Type I alveoli
95%. Squamous epithelium with central nucleus, anchored to a continuous basal lamina
Type II alveoli
5%, also known as granular alveolar cell. Cuboidal cell with microvilli that is responsible for the production of pulmonary surfactant
What is the air-blood barrier composed of?
Pneumocyte I cell, basal lamina of pneumocyte I and basal lamina of capillary endothelial cells, capillary endothelial cell, plasmalemma of RBC
Small and do not change volume during respiration
What is the respiratory pathway for birds?
Lungs, primary bronchus, secondary bronchus, parabronchus, air capillaries
What are the eight air sacs in avians?
Unpaired cervical and clavicular, paired cranial thoracic, paired caudal thoracic, and paired abdominal
Study of growth and differentiation during development
Prenatal vs. Postnatal period
Development before and after birth
Period from gametogenesis to implantation
Period from implantation to the development of primordial organs
Period from development of primordial organs to complete systems
Study of embryology concerned with abnormalities
Production of gametes (spermatozoa or ovum)
Primordial germ cells form spermatogonia. Spermatogonia mitotically divides into type A (stem cell) and type B spermatogonia. Type B mitotically divides to give a primary spermatocyte. Primary spermatocyte divides meiotically into two secondary spermatocytes. Secondary spermatocytes meiotically divide into four spermatids
When spermatids undergo metamorphosis to become spermatozoa. Chromatin forms the sperm head, golgi apparatus forms acrosomal cap, centriole encircles the flagellum, and mitochondria form middle piece of sperm
Primordial germ cell forms oogonium. Oogonium divides mitotically into primary oocyte. Primary oocyte rests until puberty. At puberty, primary oocyte divides meiotically into secondary oocyte and primary polar body. Secondary oocyte rests until fertilization. At fertilization, secondary oocyte divides meitotically into ovum and secondary polar body
What is the difference in ovulation between most domestic animals and the dog/horse?
Most animals require the secondary oocyte to be penetrated by spermatozoa before the second meiotic division. Dogs and horses primary oocyte is ovulated and both meiotic divisions after penetration of the spermatozoa
Which animal has the most chromosomes? Least?
Dog has the most with 78 (39 pairs). Cat/pig have the least with 38 (19 pairs)
What two things preceed fertilization?
Ovulation and insemination
What are the two types of insemination?
Natural and artificial
Which hormones control ovulation?
FSH and LH, produced by adenohypophysis
Under hormonal influence, what is the ruptured follicle converted into?
What is the function of the CL?
Secretes progesterone which produces uterine changes facilitating implantation and maintenance of pregnancy
Which animals are induced ovulators?
Cat and rabbit
Release more than one oocyte (ex. bitch, sow, cat)
Release only one oocyte (one offspring)
Usually 1-2 days, but 6-7 in horse and dog. 32-70 in poultry. Only 24 hours for ovum
Where does fertilization occur?
Ampullary region of the uterine tube. In dogs, infundibulum of the uterine tube.
Removal of the glycoprotein coat of sperm
Release of enzymes that allow for the penetration of the oocyte barriers
Fertilization membrane develops to prevent entry of additional sperm (polyspermy), probably as a result of chemical changes in the zona pellucida (zona reaction)
One ovum is divided to produce identical twins
Two separate ova are fertilized (fraternal twins)
Fertilized ovum is lost in the peritoneal cavity, usually resulting in early embryonic death
Dizygous twinning in cows, where one is male and one is female. Release of testosterone from the male makes the female infertile
More than one sperm penetrates the ovum. Majority die. Common in pigs
Impregnation by successive acts of coitus, resulting in offspring from different fathers (ex. cats and dogs)
When a pregnant female ovulates, conceives and produces a second younger fetus (ex. pigs)
Which species has the longest gestation period? Shortest?
Horse is about 11 months. Dog/cat about 2 months
Total or Holoblastic cleavage
In mammals, where a small amount of yolk is present and equally distributed and there is a complete division of zygote
Partial or Meroblastic cleavage
In birds, when the massive amount of yolk prevents complete division of the zygote
After 4 to 6 divisions, zygote becomes morula. 16-64 cells
What covers the lips internally and externally?
Internally by mucosa and externally by integument
What type of epithelium are the lips?
Stratified squamous epithelium. Keratinized in ruminants and horses, non-keratinized in carnivores and pigs
What are the three layers of the cheeks?
Outer skin, a middle muscular layer (buccinator muscle), internal mucosa
Cheeks have 3 layers:
What type of epithelium is the mucosa of the cheek?
Stratified squamous epithelium. May or may not be keratinized
Which animals have cheek mucosa studded with conical buccal papillae?
Where are the cheek buccal glands located, and what type of glands are they?
They are located in the propria-submucosa. They may be serous, mucous, or seromucous
What are the numerous transverse ridges of the mucosa of the hard palate called?
What type of epithelium is the hard palate mucosa?
Keratinized stratified squamous epithelium. Especially thick in ruminants
Where are palatine glands located, and what type of glands are they?
They are located in the caudal part of the hard palate. They are mucous or seromucous glands
Describe the dental pad in ruminants
Consists of heavily keratinized stratified squamous epithelium, overlying a thick layer of dense irregular connective tissue
What type of epithelium is the soft palate?
Stratified squamous epithelium
In what species are the palatine tonsils present in the soft palate?
Pigs and horses
What does the propria-submucosa of the soft palate contain?
Branched, tubuloacinar, mucous or seromucous palatine glands and lymphatic tissue
What are the functions of the tongue?
Eating, drinking, vocalization, muscular and mobile, epithelial specializations, sensitive and highly innervated, contains chemoreceptor sites