Lecture Notes for Test 1

I) Intro to A&P A) Anatomy 1) Scientific branch of study that investigates the body?s structure 2) Also examines the tie between the structure of a body part and its function(fxn) (?Form Dictates Function?) a) Ex. Bones provide strength and support(fxn) b/c they are mineralized with Ca2+ salt B) Branches of anatomy 1) Developmental Anatomy ( study of structural changes that occur between conception and adulthood) a) Embryology (i) Studies changes from conception to the end of the 8th week of development (ii) Important field because this is the time period when most birth defects occur 2) Gross/Macroscopic Anatomy (study of large body structures visible to the naked eye, such as muscles, the lungs, or the heart) a) Systematic Anatomy (i) Each of the body?s 11 systems are studied separately (circulatory, respiratory, nervous, etc) b) Regional Anatomy (i) Body structures in one particular region of the body are examined at the same time ( bones, muscles, nerves, blood vessels of the head) 3) Microscopic Anatomy (structures too small to be seen with the naked eye are studied using a microscope) a) Cytology (i) Examines structural features of cells b) Histology (i) Examines micro-thin slivers of tissue, usually that have been stained with a special dye and fixed and mounted on microscope slides 4) Radiological Anatomy(study of anatomy using X-ray technology) a) Ultrasound/ Sonography (i) One of the oldest imaging techniques (ii) Makes use of high frequency sound waves which strike internal organs and bounce back to a receiver that has been placed on the skin (iii) A computer then generates an analysis of the sound waves (iv) Think of a sonogram that generates an image of a developing fetus b) Computed Tomographic Scan(CT) (i) Formerly known as CAT scans (computer axial tomographic scan) (ii) Computer analyzed X-ray images (iii) A low-intensity X-ray tube is rotated through a 360 degree arc around the patient and the images are fed into a computer (iv) The computer then constructs an image of the internal structures at points where the X-ray beam was focused and rotated c) Magnetic Resonance Imaging (MRI) (i) Radio waves are directed at a patient lying in a chamber surrounded internally by a large electromagnetic field (ii) the magnetic field causes the protons (H+) of various atoms to align (the human body contains many protons, as a large percentage of our body is composed of water) (iii) the radio waves are then used to change the alignment of the H+ ions (iv) when the radio waves are turned off, the H+ ions realign and produce images of internal structures (v) different images can be viewed because it takes varying amounts of time for the H+ ions in different structures to reconfigure d) Positron Emission Tomographic Scan (PET) (i) Identifies the metabolic states of various tissues (most useful in analyzing the brain) (ii) Works based on the premise that active cells use energy in the form of glucose (iii) First, glucose molecules are radioactively ?labeled? (marked) and administered to the patient (iv) As the radioactivity in the glucose decays (as it is being used for energy), positively charged subatomic particles called positrons are released (v) These positrons collide with electrons, giving off gamma rays (radiation given off by cell nuclei as they lose energy- here, from the collision of particles) (vi) The gamma rays are then used to pinpoint cells that are metabolically active, which is directly related to whether are not they are functional C) Physiology 1) Scientific investigation of the fxn of living things 2) Major goals a) Understand how the body maintains conditions with in a narrow range of values (homeostasis) (i) T= 98.5 (ii) Heart rate= 72 BPM (iii) Blood pressure= 120/80 mmHg (iv) Urinary output= 1.5 L/day b) Understand & predict how the body will respond to stimuli or changes D) Branches of Physiology 1) Cellular Phys- studies processes occurring in individual cells 2) Neurophysiology- studies processes occurring in nervous system 3) Renal phys- studies kidney fxn and urine production 4) Cardiovascular phys- studies fxn of blood, heart, and blood vessels E) Levels of Structural Organization (least ï? most) 1) Chemical level a) Atoms combine to form molecules b) Molecules combine to form cellular organelles 2) Cellular level a) Cells are the basic units of all living things b) All body cells have a certain # of fxns in common (i) Ex. Cellular respiration c) Cells can have unique fxns (i) Ex. Muscle cells contract 3) Tissue level a) A tissue is a group of functionally similar cells b) 4 tissue types: (i) Epithelium- covers body surfaces and lines cavities (ii) Muscle- movement (iii) Connective- support and protect (iv) Nervous- provides communication through electrical signaling 4) Organ Level a) An organ is composed of at least 2 tissue types that perform a common fxn (i) Ex. Kidney and liver 5) System Level a) A system is a group of organs with a common fxn and are viewed as a unit b) Body is divided into 11 distinct systems (fig 1.3 text- 2 pages) (i) Circulatory System- Pumping blood to and from the body and lungs with the heart (ii) Digestive system- digestion and processing of food with salivary glands, esophagus, stomach, liver, gall bladder, pancreas, intestines, rectum, and anus (iii) Endocrine system- communication within the body using hormones made by endocrine glands such as the hypothalamus, pituitary or pituitary glands, pineal body or gland, thyroid, parathyroids, and adrenals or adrenal glands (iv) Immune System- protection against disease-causing agents with leukocytes, tonsils, adenoids, thymus, and spleen (v) Integumentary system- skin, hair, and nails (vi) Lymphatic system: structures involved in the transfer of lymph between tissues and the blood stream, the lymph and the nodes and vessels that transport it including the immune system (vii) Muscular Systems- movement with muscles (viii) Nervous System- collection, transferring and processing information with brain, spinal cord, peripheral nerves, and nerves (ix) Reproductive system- the sex organs. Includes ovaries, fallopian tubes, uterus, vagina, mammary glands, testes, vas deferens, seminal vesicles, prostate, and penis. (x) Respiratory system- the organs used for breathing, the pharynx, larynx, trachea, bronchi, lungs, and diaphragm (xi) Skeletal system- structural support and protection with bones, cartilage, ligaments, and tendons. 6) Organism Level a) Any living organism considered as a whole II) Terminology and Body plan A) Body Positions 1) Anatomic position a) Subject is: (i) Standing erect (ii) Facing forward (iii) Limbs hanging at side (iv) Palms facing forward 2) Supine a) Laying on back, facing forward 3) Prone a) Laying on belly, facing down B) Directional Terms 1) Superior a) Towards the head; above b) Aka. Cranial, cephalic c) ex. Shoulder is superior to pelvis 2) Inferior a) Away from the head; below b) Aka. caudal 3) Anterior a) In front of b) Aka. Ventral 4) Posterior a) In back of, behind b) Aka. Dorsal 5) Medial a) Toward midline of body, on inner side 6) Lateral a) Away from the midline, on outer side 7) Proximal a) Closer to the point of attachment (of a limb to the body trunk) 8) Distal a) Further from the point of attachment (of a limb to the body trunk) 9) Superficial a) Toward body surface b) Aka. External 10) Deep a) Away from surface of body b) Aka. Internal C) Body Regions & Planes 1) 2 main regions: a) Axial- head, neck, trunk b) Appendicular- appendages/limbs 2) 3 main planes: a) Saggital- vertical plane dividing body into right and left halves (i) Mid-saggital- equal halves (ii) Para-saggital- unequal halves b) Frontal- vertical plane that divides into anterior & posterior halves c) Transverse- horizontal plane that divides into superior & inferior halves D) Body Cavities 1) Dorsal Body Cavity- protects nervous system organs a) Cranial Cavity- encases brain b) Vertebral Cavity- encases spinal cord 2) Ventral Body Cavity- location of internal organs (viscera) a) Thoracic Cavity (chest)- (i) Surrounded by ribs and muscles of the chest (ii) 2 subdivisions ï?? Lateral pleural cavities, each containing a lung ï?? Medial pericardial cavity, contains heart b) Abdominopelvic Cavity (i) Separated from thoracic by the diaphragm (ii) 2 regions ï?? Abdominal Cavity- stomach, intestines, liver, spleen, pancreas, & kidney ï?? Pelvic Cavity- urinary bladder, last part of large intestine, internal reproductive structures E) Membranes in the Ventral Body Cavity 1) Serous membranes- double walled membrane that covers organs and liens cavity walls a) Parietal Serosa- part of membrane that lines cavity walls b) Visceral Serosa- part of membrane that covers the organs c) Serous Fluid- thin layer of lubricating fluid between ?serosas? 2) Specific Terms a) Parietal pericardium- lines the pericardial cavity b) Visceral pericardium- lines walls of pleural cavities c) Parietal pleura- lines walls of pleural cavities d) Visceral pleura- covers lungs e) Parietal peritoneum- lines walls of abdominopelvic cavity f) Visceral peritoneum- covers surface of most organs in abdominopelvic cavity III) The Cell A) Plasma Membrane (PM) 1) General characteristics: a) Outermost component b) Responsible for cells ability to connect, recognize, and *communicate with each other c) Substances inside PM are intracellular and ones outside are extracellular 2) Structure a) Lipids (40-50% of PM) (i) Phospholipids- lipids joined with phosphate groups; 2 layers (?Lipid Bilayer?) ï?? Hydrophilic heads (H2O loving) are made of phosphate (polar) ï?? Hydrophobic heads (H2O hating) are made of fatty acid chains (nonpolar) (ii) Cholesterol- interspersed between phospholipids, prevents fatty acid chains from sticking ï?? Maintains flexibility & fluidity, which is critical to fxn b) Proteins (45050% of PM) (i) Suspended within PM (ii) 2 general types ï?? Integral- inserted all the way through PM 1. PM can communicate with both intracellular and extracellular fluid simultaneously ï?? Peripheral- attached to either the inner or the outer surface of PM 1. can only communicate with intracellular or extracellular fluid (iii) Fxns ï?? Attachment sites- allow cells to attach to each other or to extracellular molecules ï?? Ion Channels- allow ions (Na+, K+, Cl_) to move into or out of cell ï?? Receptor Molecules- site on PM that binds a specific substance; binding causes a chain of intracellular events 1. Acetylcholine 2. end result=contraction= SIGNAL TRANSDUCTION ï?? Marker Molecules- allow for cellular recognition 1. ex. Sperm cell is recognizing oocytes 2. immune system recognizing ?self-cell? vs. ?foreign cell? c) carbohydrates (i) CHO + lipid = glycolipid (ii) CHO + protein = glycoprotein B) Cellular Transport Mechanisms 1) Passive Transport a) Doesn?t require energy (ATP) b) Involves the movement of solutes from an area of high concentration to an area of lower concentration (i) i.e. DOWN a concentration gradient c) Simple Diffusion (i) Result of the constant random motion of all atoms, molecules, and ions in a solution (ii) Rate of diffusion ^ as temp ^ (iii) Rate of diffusion decreases as particle size ^ d) Facilitated Diffusion (i) Thee diffusing substances binds with a carrier protein on the outer or inner surface of the PM ï?? Binding causes a conformational change in carrier protein e) Osmosis (i) The movement of H2O from an area where there are less solutes to an area where there are more solutes (ii) When comparing 2 solutions across a membrane: ï?? The solution with more solutes is Hypertonic ï?? The solution with less solutes is Hypotonic ï?? If both solutions have the same number of solutes they are Isotonic ï?? **H2O will always move from a HYPO- to a HYPER- solution 2) Active Transport a) Requires energy (ATP) b) Involves the movement of solutes from an area of lower concentration to an area of higher concentration (i) UP/AGAINST concentration gradient c) Primary Active Transport (i) Ex. Na+/K+ ATPase pump on PM of cells ï?? Pump moves Na+ and K+ against their concentration gradients using energy gained from enzymatically splitting ATP (ADP + Pi + nrg) 1. more Na+ in extracellular fluid than intracellular fluid 2. more K+ in intracellular fluid than extracellular fluid 3. moves 3 Na+ out of cell towards ^ concentration 4. moves 2 K+ into the cell towards ^ concentration 5. **keep levels of Na & K different; by simple diffusion, they will move with their gradient 6. **in an excitable cell, both are occurring C) Generating and Maintaining a Resting Membrane Potential(RMP) 1) Membrane potential is the generation of ?voltage? (nrg) in the form of electricity by separation of oppositely charged particles across a membrane 2) RMP is the charge on an Excitable Cell?s plasma membrane when the cell is at rest. (Two examples of excitable cells are nervous tissue and muscle tissue) a) Usually -90 to -70 millivolts (i) The ?-? (negative sign) means the inside of the cell is more negative than the outside b) At rest, the ell is said to be polarized (separation of charges exist) c) The negativity inside the cell is due to: (i) At rest the membrane is more permeable to K than it is to Na ï?? This means that a lot more K moves passively down its gradient out of the cell, taking its positive charge with it ï?? This also means less Na moves passively down the gradient into the cell; but not all positive charges are replaced (ii) There is a large concentration of negatively charged intracellular proteins that are always impermeable d) Role of the sodium/potassium pump (i) The pump actively ?kicks out? some of the Na that passively moved in (ii) The pump actively ?pulls in? some K that passively moved out ï?? **this maintains differential concentration gradients for Na and K; these gradients store energy for nerve and muscle function IV) Tissues A) Four types: epithelial, connective, muscle, and nervous B) Classified based on: 1) Structure of cells 2) Composition of non-cellular substances surrounds the cell (extracellular matrix) C) Epithelial tissue 1) Covers body surfaces and lines body cavities 2) Forms some glands 3) Retains mitotic ability a) Mitotic ability(defined) means that damaged cells can be replaced with new ones 4) Epithelial tissue has two surfaces a) The apical surface is exposed to body exterior or faces the cavity of an internal organ (also known as the ?free surface?) (i) It can have microvilla (finger-like projections from PM) used to ^ surface area in a cell (ii) It can have cilia (hair-like; used to move substances forward) b) The basal surface is opposite of the apical surface and is in contact with (attached to) the structure the epithelium is covering or lining (i) Basal membrane is usually associated with a basement membrane (ii) Extracellular material secreted by epithelial cells in basal membrane (iii) Function of basal membrane: attachment of cells to structure that is covering the lining and guide cell migration during tissue repair 5) Epithelial tissue with one layer is a simple epithelial layer. Epithelial tissue with multiple layers is stratified epithelial tissue 6) Function of epithelial tissue: a) Protection (skin) b) Secretion (sweat glands) c) Absorption (intestinal) D) Connective Tissue (CT) 1) Eyes 2) Each major class of CT has a predominate cell type that exists in immature(I) and mature(M) form a) CT (i) Loose and dense (ii) Cartilage (iii) Bone (iv) Blood b) (I) Cell Type (i) Fibroblast (ii) Chondroblast (iii) Osteoblast (iv) Hemopoietic stem cell c) (M) Cell Type (i) Fibrocyte (ii) Chondrocyte (iii) Osteocyte (iv) Erythrocyte(red blood cell) (v) Leukocyte(white blood cell) (vi) Thrombocyte(platelet) 3) Specific Functions a) Loose Connective Tissue (CT) (i) Areolar ï?? Attaches skin to underlying structures (ii) Adipose(flat) ï?? Yellow 1. storage, insulation, protection ï?? brown 1. found mostly in armpits, neck, and near kidneys 2. generates heat, especially in a newborn b) Dense Connective Tissue (CT proper) c) Cartilage (i) Hyaline (most abundant) ï?? Made of small collagen bundles ï?? Found where support and flexibility is needed 1. Costal cartilage of ribs 2. nose 3. trachea 4. articulating surfaces E) Nervous Tissue 1) Found in brain, spinal cord, & fibers extending from these areas 2) Controls body fxns through electrical signals called Action Potentials 3) Two major cell types: a) Nervous/cell types: (i) Actual conducting cells; produce AP?s b) Neurologlia (glial cells) (i) Non-conduction cells(do not AP?s) (ii) Support cells that provide insulation and protection to neurons F) Muscle Tissue 1) Responsible for movement 2) Contracts (shortens) in response to electrical signals a) Contraction occurs due to the interaction of cellular proteins called actin and myosin 3) When described according to structure: a) Striated structures are visible microscopic bands of actin and myosin b) Smooth structures do not have bands that are visible 4) When described according to FXN: a) Voluntary fxns can be controlled consciously b) Involuntary fxns are controlled unconsciously 5) There are three muscle types: a) Skeletal muscle (i) Packaged in CT attached to bone (ii) Cells are multinucleate (iii) Striated, voluntary b) Cardiac muscle (i) Found only in heart (ii) Cells are mononucleate (iii) Striated, involuntary c) Smooth muscle (i) Found in walls of hollow organs ï?? Ex. Blood vessels and small intestines (ii) Cells are mononucleate (iii) Unstriated, involuntary ï?? *Unstriated is the same thing as smooth V) Integument system A) The skin 1) The skin is the larges organ of the body 2) Composed of two general regions: a) Epidermis(skin; outermost region) (i) Stratified squamous epithelium (ii) Most cells produce the protein keratin (which provides protection) (iii) New cell production occurs by mitosis in deeper layers; surface cells die and desquamate (iv) Five strata (layers) ï?? Stratum corneum is the ?hard layer? 1. most superficial 2. thickest layer, 20-30 layers of dead cells filled with keratin 3. has waterproofing glycolipids that are produced in a deeper layer ï?? Stratum lucidum is the ?clear layer? 1. 2-3 layers of dead cells filled with keratin 2. only present in ?thick skin? ï?? Stratum granulosum is the ?granular layer? 1. 3-5 layers of cells that are alive but organelles are degeneration 2. 2 types of granular producing cells: a. Keratinocytes produce keratohyaline granules which secrete Keratin b. Lamellar bodies produce lamellated granules that secrete the glycolipids found in stratum corneum ï?? Stratum Spinosum is the ?spiny layer? 1. 5-7 layers of living cells 2. has melanin granules a. produced in deeper layers 3. has Langerhan?s cells a. immune cells that have migrated from bone marrow ï?? Stratum basale is the ?basal layer? 1. deeper layer 2. made of one layer of rapidly dividing epithelial cells that migrate to more superficial layers 3. has melanocytes that produce the melanin granules found in the Spinosum 4. has cells called Merkel Discs a. touch receptors b) Dermis (innermost layer) (i) Dense irregular connective tissue (ii) Has: ï?? Blood vessels ï?? Nerve endings ï?? Hair follicles ï?? Glands ï?? Smooth muscle (iii) Composed of two layers: ï?? Papillary layer 1. immediately below stratum basale 2. made of areolar connective tissue 3. dermal papillae on palms and soles to yield ?fingerprints? ï?? Reticular layer 1. 80% of dermis 2. dense, irregular CT c) hypodermis (i) the hypodermis is deep to the dermis (lower than) (ii) Not considered a ?true layer? but has important fxns: ï?? stores fat for insulation and shock absorption ï?? Anchors skin to underlying bone and muscle ï?? Pathway for blood vessels and nerves to reach superficial layers B) Accessory Skin Structure 1) Sweat gland a) Merocrine/eccrine- this is the most common sweat gland, it is located mostly in palms and forehead (i) The secratory portion found coiled deeply in epidermis (ii) The releasing duct extends to surface of epidermis (iii) Secrete sweat made from water and salt used for evaporative heat loss b) Apocrine glands (i) These glands are less abundant than merocrine, but they are larger (ii) The coiled secratory portion of this gland has the releasing duct open into hair follicle (iii) These glands are located in the axillary(armpit) and pubic regions (iv) These secretions contain organic substances that are odorless when released but become odiferous once bacteria breaks down organic substances (v) The glands are not active until puberty 2) Sebaceous Glands a) These glands are present everywhere except for palms and soles b) Secretion- these glands secrete sebum that is made of oily lipids and cell fragments. It is used to soften and lubricate hair and skin c) When sebaceous gland become blocked by excess sebum it creates a pimple 3) Hair and hair follicles a) Structure: (i) The shaft is the part located above the skin (ii) The root is the part embedded in the skin (iii) Hair is arranged in three concentric(circular) layers of dead, keratinized epithelial cells ï?? Medulla: central axis, made of soft keratin ï?? Cortex: bulk of hair, made of hard keratin ï?? Cuticle: outermost keratinized layer (iv) The hair follicle wraps around the root and is embedded in skin ï?? Deep and expands into hair bulb ï?? Associated with each follicle are smooth muscle cells called Arrecctor pili muscles 1. muscles contract in response to cold temperature, touch, and emotional distress, pulling the follicle upright (causing hair to ?stand on end?) 4) Nails a) Nails are scale-like modification of the epidermis b) The nail root is the proximal end covered by skin c) The nail body is the portion of the nail that you see d) The nail fold is the later end (side of nail) that is covered by skin e) The nail groove holds edges of the nail in place f) The free edge is the portion of nails that extends past the fingertip g) The eponychium (cuticle) is the stratum corneum of the nail fold that has grown over the nail body h) The lunula is the crescent shaped white area above the cuticle (i) The deeper layers of the epidermis extended beneath the nail as the ?nail bed? ï?? The proximal portion of the nail bed is the nail matrix and is responsible for nail growth C) Integument System Fxns 1) Protection a) Chemical barrier (i) Skin secretions are slightly acidic, so they slow the growth of the bacteria (ii) Melanin in skin protects against UV rays b) Physical barrier (i) The continuity of skin and the hardness of keratinized cells limit the entry of foreign substances (ii) Glycolipids make skin waterproof (iii) Hair on head provides insulation, eyebrows slow the flow of sweat into eyes, hair in the nose and ears is used to trap airborne particles (iv) Nails cover the ends of fingers and toes to aid in physical protection c) Biological Barriers (i) Langerhan?s cells, found in stratum Spinosum, help activate the immune system (ii) Dermal macrophage?s are phagocytic cells in the dermis that protect against micro-organisms 2) Body temperature regulation a) An increase in temperature activates secratory activity of sweat glands, when the sweat evaporates it pulls heat away from skin 3) Sensation a) Touch receptors are located in the epidermis (also known as Merkel discs) and are founding the stratum basale b) Located in the dermis are: (i) Touch receptors, also known as Meissher?s Corusches (ii) Pain receptors, also known as noiceptors (iii) Temperature receptors, also known as Thermoreceptors (iv) Pressure receptors, also known as pacinian corpuscles 4) Clinical disorders a) Skin cancer is caused by genetic predisposition and exposure to UV radiation (i) Basal cell carcinoma is the least malignant skin cancer, but also the most cmmon ï?? Basal cell carcinoma begins in the stratum basale. It starts when disuse destruction produces an open ulcer. It is treated by surgical removal, or in severe cases, radiation treatment. (ii) Squamous cell carcinoma ï?? Squamous cell carcinoma consists of cells that have migrated from the stratum basale and continue mitotic growth (cells should no longer be capable of mitosis once leaving the basale layer) ï?? This cancer originates in stratum Spinosum ï?? In rare cases the tumor will migrate out of the epidermis and enter the dermis; if this occurs the tumor can metastasize 1. **this cancer can become fatal (iii) Malignant Melanoma is the most harmful type of skin cancer, but the least common ï?? malignant melanoma arises from melanocytes, usually from a pre-existing mole ï?? this cancer develops as a large, flat spreading sore or a deeply pigmented nodule(a nodule is a hard lump under the skin) ï?? Metastasis is a common, malignant melanoma that must be detected and treated very early 1. *Malignant melanoma is usually fatal b) Burns (i) Burns are categorized by the depth of cell damage ï?? 1st degree burns involve the epidermis only 1. 1st degree burns are red and painful but they heal within a week without scarring ï?? 2nd degree bunds damage the epidermis and the dermis 1. 2nd degree burns are red an very painful 2. they are usually associated with edema, or swelling (loss of fluid from vessels into tissue spaces) 3. burn blisters usually develop 4. 2nd degree burns usually heal in 1-2 weeks and the degree of scarring depends on how much dermis was damaged ï?? 3rd degree burns completely destroy the epidermis and dermis 1. skin can regenerate only from the edges, which makes skin grafts often necessary 2. The pain associated with 3rd degree burns comes from deeper tissue than 2nd degree burns. 3. **3rd degree burns kill nerve endings VI) Skeletal System A) Functions B) Cartilage C) General bone characteristics 1) 206 bone names 2) Each bone is an organ 3) Made of living tissue that grows and repairs 4) Axial Skeleton a) Fxn: protection and support b) Includes: (i) Skull (ii) Vertebralcolumn (iii) Ribcage 5) Appendicular Skeleton a) Fxn: movement b) Includes: upper and lower limbs 6) Four bone shapes: a) Long bones (i) Longer than wide (ii) Ex. Most bones of upper and lower limbs (humerus, tibia) b) Short bones (i) Short bones are about as wide as they are long (ii) Ex. Most bones of the wrist and ankle c) Flat bones (i) Thin, flat, usually curved (ii) Ex. Some skull bones, ribs, sternum, and scapula d) Irregular Bones (i) Odd shape (ii) Ex. Vertebrae, patella(sesamoid bone) D) Long Bone structure 1) Diaphysis a) Shaft that forms the long axis b) Composed of compact bone 2) Epiphysis a) ?knobs? at end of long bones b) Composed mostly of spongy/cancellous bone 3) Epiphyseal Plate a) Hyaline cartilage b) Area of growth (i) At the end of growth period, gets completely transformed into bone and is called the Epiphyseal line 4) Medullary Cavity a) In Diaphysis of long bone b) In children, it contains red bone marrow c) In adults, the red bone marrow has been replaced by yellow bone marrow 5) Periosteum (?peri?=around/outside, ?osteum?= bone) a) CT membrane covering outer surface of bone b) Two layers (i) Outermost= dense irregular CT (ii) Innermost= 2 cell types ï?? Osteoblasts are bone-forming cells ï?? Osteoclasts are bone restoring cells c) Sharpey?s fibers secure tendons and ligaments to bone 6) Endosteum (?endo?=inner) a) CT membrane lining inner bone surfaces E) Short, Flat, Irregular Bone Structure 1) Flat bones a) Usually no epiphysis or diaphysis b) Spongy bone in flat bone is called dipolë, which is between two layers of compact bone 2) Short and Irregular Bone a) Spongy bone center b) Compact bone on outer surface F) Microscopic Anatomy of Compact Bone 1) Organized in structured units called osteons a) Lamellae are circular layers of bone matrix b) Lamellae surround a common center called Haversian Canal (i) Passageway for blood vessels and nerves c) At junctions of lamellae are small cavities called lacunae (i) Contain osteocytes d) Small canals called canaliculi connect lamellae to each other and to the Haversian Canal (i) Fxn: Waste and nutrient exchange in a blood vessels for osteocytes G) Bone Development 1) Process called osteogenesis (or ossification) 2) Begins eight weeks after conception 3) At birth, most long bones are well ossified except at the epiphyseal plates a) Complete ossification is the end of the growth period (then called ?epiphyseal line?) 4) Bones of Skull do not begin to ossify until week 10 post-conception a) Not completely ossified at birth, connected by fibrous membranes called fontanels (i) Allow head to be compressed during birth (ii) Accommodate rapid brain growth and development b) Final ossification is at 2 years of life H) Bone Growth (length only) 1) Growth in bone length a) New bone is formed on surface of cartilage (or old bone) b) Occurs at epiphyseal plate (i) Plate is organized into 4 zones ï?? Zone of resting cartilage 1. nearest the epiphysis 2. contains randomly arranged chondrocytes that are slowly dividing ï?? Zone of proliferation 1. chondrocytes are producing new cartilage through intestinal growth and are undergoing rapid growth ï?? Zone of hypertrophy 1. chondrocytes that were produced in the zone of proliferation mature and enlarge ï?? Zone of calcification 1. consists of cartilage matrix mineralized with calcium 2. hypertrophy chondrocytes die; blood vessels intrude the area 3. CT surrounding blood vessels contains Osteoblasts; they deposit new bone matrix on top of calcified cartilage (Appositional growth) I) Factors affecting bone growth 1) Nutrition a) Vitamin D (i) Needed for absorption of calcium in small intestine (ii) Deficiency in children can lead to rickets(a disease characterized by a reduced mineralization of bone matrixï? bones ?bow?) (iii) Adults with inability to metabolize vitamin D can develop osteomalacia softening, which is the softening of bones as a result of calcium depletion b) Vitamin C (i) Necessary for collagen synthesis by Osteoblasts (ii) Deficiency can result in scurvy, a disease characterized by ulceration and hemorrhage of skin (due to lack of normal collagen in CT) 2) Hormones a) Two hormones regulate the exchange of calcium between the blood and bone (i) Calcitonin ï?? Synthesized by the Thyroid gland ï?? Promotes incorporation of calcium from blood into bone ï?? Sensitive to circulating estrogen hormones 1. increase estrogen, increase calcitonin, incorporation into bone 2. decrease estrogen, decrease calcitonin 3. release, decrease calcium incorporation into bone 4. menopausal hormones may develop osteoporosis (brittle bones due to decrease in calcium deposit into bone) (ii) Parathyroid hormone ï?? Synthesized by parathyroid gland ï?? Signal for release is increased Plasma calcium levels ï?? Mobilizes calcium stored from bone into blood VII) Articulations and movement A) Classes of joints 1) Fibrous joints a) Two bones united by fibrous CT b) Exhibit very little to no movement c) Classified into three groups based on structure (i) Sutures ï?? Seams between skull bones ï?? Very stable because the opposing bones have what are called interlocking processes ï?? Ex. Coronal suture between frontal and parietal bones ï?? Ex. Lambdoid suture between occipital and parietal bones (ii) Syndesmosis ï?? Fibrous join that joins bones via ligaments ï?? Ligaments are flexible so some movement can occur ï?? Ex. Tibiofibular joint between tibia and fibula (iii) Gomphoses ï?? Specializing joints consisting of ?pegs and sockets? ï?? Held in place by fibrous CT called periodontal ligaments ï?? only between teeth and mandible/maxilla 2) Cartilaginous Joints a) Two bones united by hyaline or fibro-cartilage b) Classified in two groups: (i) Synchondioses ï?? Bones joined by hyaline cartilage ï?? Little to no movement ï?? Ex. Epiphyseal plate between epiphysis and diaphysis of growing bone ï?? Ex. Between costal cartilage of first rib and manubrium (ii) Symphyses ï?? two bones untied by fibrocartilage ï?? flexibility; some movement is allowed ï?? ex. Pubic Symphyses ï?? ex. Intervertebral disks c) Synovial Joints (i) Articulating bones are separated by fluid-filled cavity ï?? Fluid is called synovial fluid ï?? These include most joints of the body (all joints of the articulating limbs) ï?? Highly moveable ï?? Structure: 1. Articular cartilage a. Ends of opposing bones are covered with hyaline cartilage b. Absorbs compression 2. Joint Cavity (synovial cavity) a. Unique to synovial joints b. Cavity is a potential space that holds a small amount of fluid 3. Articular capsule a. Joint cavity is enclosed in a two-layered capsule 4. Fibrous capsule a. Dense irregular connective tissue- strengthens joint 5. Synovial Membrane a. Loose CT b. Lines joint capsule and covers internal joint surfaces c. Fxn: make synovial fluid 6. Synovial Fluid a. Viscous fluid similar to raw egg white b. A filtrate of blood c. Arises from capillaries in synovial membrane d. Contains glycoprotein molecules secreted by fibroblasts 7. Reinforcing ligaments a. Often are thickened parts of the fibrous capsule b. Sometimes are extracapsular ligaments (located outside the capsule) c. Sometime are intracapsular ligaments (located inside the capsule