Lungs – O2, CO2, water, heat
Skin – sweat (salt, urea, water, heat, HCO3)
Digestive tract – elimination of food residues & metabolic waste products
Urinary system – elimination of nitrogen-containing wastes, water, salts, and ions
1. Excretion of metabolic wastes (nitrogen-containing compounds)
2. Maintains fluid balance in the body – regulates the volume of our blood so that we have enough interstitial fluid to service the muscles
3. Maintains pH
4. Produce erythropoietin (stimulates RBC production in kidneys)
5. Transform vitamin D to its active form – manage calcium and phosphorus in the body
6. Remove foreign compounds
Urea – ammonia formed in liver during breakdown of amino acids; very toxic
Uric acid – formed in breakdown of nucleic acids; forms crystals in synovial fluid of joints (painful)
Creatinine – formed in skeletal muscle from the breakdown of Creatine phosphate (regenerator of ATP in muscle cells)
2 Kidneys – produce urine, conserve water, regulate pH, stimulates production of RBC’s, and transforms vitamin D to active form
2 Ureters – transport urine from kidneys to the bladder via peristaltic contractions
Urinary bladder – stores urine
Urethra – transports urine from urinary bladder to outside of the body
What is the urination reflex? How is it stimulated, and what does it involve?
Bladder fills --> stretch receptors send impulses to spinal cord --> impulses cause the detrusor muscle in the bladder to contract and internal urethral sphincter to relax --> impulses in brain initiate desire to urinate --> voluntary relaxation of the external urethral sphincter --> urine exits body
What is the detrusor muscle?
Smooth muscle in the wall of the bladder that is stimulated to contract as the bladder fills
What are the internal urethral sphincter and the external urethral sphincter? What do they do, how are they similar and how do they differ?
What is urinary incontinence and what are the possible causes? What does an overactive or spastic bladder mean?
Urinary incontinence – inability to exert voluntary control over urination
- Children younger than 2 or 3
- Adults with damage to external urethral sphincter caused by:
Prostate surgery in men
Overactive or spastic bladder – bladder muscles contract before it is full
Urinary system infection
Stress incontinence in pregnant women
Kidney – regulates the makeup of the extracellular fluid (interstitial fluid and plasma) by filtering the blood and forming urine
Outermost layer – tough and fibrous; anchors each kidney and its adrenal gland to the abdominal wall and surrounding tissues
Middle layer – protective cushion of fat; adipose capsule
Innermost layer – collagen fibers that protect the kidneys from trauma
Renal cortex – outer region that extends in renal columns between renal pyramids
Renal medulla – middle region containing renal pyramids
Renal pelvis – inner chamber and collecting space for urineAdrenal glands – located on the top of the kidneys; secretes hormones
Afferent – incoming arteriole that carries blood to the capillaries in the glomerulus
Efferent – outgoing arteriole that carries blood from the capillaries to the renal tubule
Peritubular capillaries – capillaries surrounding the nephron; receive blood from the efferent arteriole and send it to venules to the renal vein
Peritubular fluid – interstitial fluid surrounding the nephron
What is the course that blood takes through the kidneys?
What is proximal convoluted tubule?
What is the loop of Henle?
What is the distal convoluted tubule?
What is the collecting duct?
What are podocytes?
Epithelial cells in the proximal convoluted tubule contain microvilli that increase surface area for absorption; these are not present in the loop of the nephron or the distal convoluted tubule
What are the Three Urine-forming Processes performed by the Nephron?
1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion
Water and small solutes (anything small enough) in the blood move through the walls of the Glomerular capillaries and into the space in the Glomerular capsule in the renal corpuscle; 180 liters of per day; 2.75 liters of plasma in the body
Removes useful materials (water, ions, nutrients) from the filtrate and returns them to the blood in the renal tubule, specifically the proximal convoluted tubule
Removes additional wastes, excess ions, and foreign substances form the blood in the proximal convoluted tubule, distal convoluted tubule, and connecting duct
Proximal convoluted tubule reabsorbs water, glucose, amino acids, some urea, Na+, Cl-, HCO3+ into capillaries; move along concentration gradients
What are the differences in solute concentrations between the fluid in the descending limb and in the peritubular fluid?
What are the differences in solute concentrations between the fluid in the ascending limb and in the peritubular fluid?
Distal convoluted tubule – filtrate is hypotonic (low concentration of solute)
What are the differences in solute concentrations between the fluid in the collecting duct and in the peritubular fluid?
How do these characteristics provide the kidney with the ability to secrete Hyperosmotic urine?
What happens to the fluid in the collecting ducts with respect to water? How does this happen? What about H+?
What is the fluid in the collecting ducts called, and where does it go from there?
What is micturition?
Urine – yellowish fluid produced in the kidneys containing waste and excess materials removed from the blood; travels down the ureters to the urinary bladder, where it is stored until being excreted from the body through the urethra
Contains: H2O, urea, uric acid, creatinine, ammonia, bicarbonate, Na+, K+, and other ions
Does not contain: glucose, plasma proteins, RBC’s, hemoglobin, WBC, or bile
How does the kidney participate in regulating the pH of the blood and the interstitial fluid?
How can dysfunctional Na+ regulating mechanisms in kidney contribute to Hypertension?
What are kidney stones?
What is renal failure and uremia? What are the causes? How is it treated? What are the symptoms?
Renal failure – number of functional nephrons becomes too low to purify blood because Glomerular filtration stops taking place
Uremia – toxins in kidneys
Causes: acidic blood pH, anemia due to lack of erythropoietin, edema (swelling of body tissue), hypertension, build up of nitrogenous waste
Symptoms: diarrhea, vomiting, labored breathing, irregular heart rate, convulsions, coma, and death within a few days
Treated by: kidney transplants or use of an artificial kidney machine
What is Hemodialysis? What is an artificial kidney machine? How does it work?
Hemodialysis – the use of artificial devices to cleanse the blood of wastes and excess fluid
Artificial kidney machine – blood is removed from person, feeds through tubes in machine that regulate the composition of the blood using dialyzing fluid, and blood is returned to the person
CAPD – continuous ambulatory peritoneal dialysis; dialyzing fluid flows from a bad into the abdominal cavity, where wastes in the nearby blood vessel move across the peritoneum and into the dialyzing fluid; the dialyzing fluid containing wastes is drained from the abdominal cavity and discarded
Ingestion, breakdown, absorption, elimination of undigested materials
Long tube that begins with the mouth and ends with the anus; the lumen inside of the tube is not considered part of the internal environment of the body
Mouth/oral cavity, pharynx, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, ascending colon, transverse colon, descending colon, rectum, anal canal), anus
Salivary glands, pancreas, liver, gall bladder
What are the Four Stages of Food Processing?
What is Ingestion?
Digestion – breakdown of the molecules so that they can be absorbed
Carbohydrates break down to smaller polysaccharides and monosaccharides, proteins break down to amino acids, fats break down to lipids, and nucleic acids break down to nucleotides
Chemical breakdown/hydrolysis – enzymes secreted by the GT tract or accessory organs break molecules into smaller subunits that can be absorbed into the blood and used by the cells
Absorption – break down of raw materials, water, and high-energy molecules
Elimination – anything that wasn’t digested and absorbed is eliminated in the form of feces (not necessarily metabolic waste like in the urinary system because the material has never been in the internal environment of the body)
Hollow tube throughout (lumen)
Mucosa – the innermost layer of the GI tract; moist and mucus-secreting
Submucosa – next innermost layer consists of connective tissue containing blood vessels, lymph vessels, and nerves
Muscularis – next layer responsible for movement of materials through the GI tract; double layer of smooth muscle (circular inner layer contracts to decrease opening and longitudinal outer layer contracts to adjust the tube length; opposing muscles)
Serosa – outermost thin layer of epithelial tissue supported by connective tissue; secretes a fluid that lubricates the outside of the GI tract
Salivary glands secrete saliva, which moistens the food; parotid glands are located on the side of the face in front of the ear, sublingual glands are located under the tongue, and Submandibular glands are located under the jaw
Saliva contains: slippery glycoproteins that lubricate and bind the food; buffers that neutralize acids to avoid tooth decay; Lysozyme, a protein that pokes holes in bacteria to kill them; salivary amylase that breaks down starch into smaller saccharides; and water that moistens food and solublizes compounds in the food so we can taste them
What Mechanical and chemical processing begins in the oral cavity and how are these accomplished?
Mechanical (teeth) and chemical (salivary amylase) digestion of god begins, food quality is monitored, and food is moistened and manipulated
Teeth mechanically break down food for swallowing and increase surface area for digestive enzymes to work on; mastication is chewing; nothing relevant to the digestive system is absorbed in the oral cavity
Tongue is a skeletal muscular organ covered with taste buds; allows for taste, monitors food quality, contributes to speech sounds, manipulates food for chewing (bolus – small mass that food is manipulated into that makes it easier to swallow), initiates swallowing reflex by pushing food to the back of the throat
Where and what is the pharynx and what does it do?
How does Swallowing occur? Is it a voluntary or an involuntary process? Why doesn’t food go up into your nasal cavities or down into your trachea when you swallow it?
Tongue voluntarily pushes bolus into the pharynx; in the pharynx, the process becomes involuntary and sensory receptors in the wall of the pharynx detect the presence of food and stimulate the swallowing reflex; food does not enter nasal cavities because of reflex movement of the soft palate and the movement of the epiglottis over the glottis of the larynx
Esophagus is a muscular tube that conducts food from the pharynx to the stomach by peristalsis; sphincter is a ring of smooth muscle at each end of the esophagus; Pharyngoesophageal sphincter at the pharynx prevents food from going backward into pharynx and Gastroesophageal sphincter at the stomach end prevents gastric juices from leaking back into the esophagus; heartburn occurs when the gastric juices leak back into the esophagus
Stomach is a muscular sac that is well designed to 1) store food and regulate its release to the small intestine 2) mechanically liquefy food and 3) chemically break down food with enzymes and acids; chyme is the soupy mixture of food and gastric juices; gastric juice is the mixture of HCl and pepsin (activated form of pepsinogen by HCl)
Where is the pyloric sphincter and what is its function?
What are the functions of Goblet cells, Parietal cells, and Chief cells?
HCl breaks down plant cell walls and the connective tissue in meat, kills microorganisms, and activates pepsinogen (inactive form of pepsin) into pepsin (active protein-digesting enzyme)
The stomach is not digested by its own secretions because of mucus on the stomach wall, pepsinogen cannot digest the cells that produce it, less gastric juice is produced when there’s not food to absorb it, and the stomach lining can be quickly repaired
Chemical digestion and absorption; duodenum is the first division, it receives chyme from the stomach and digestive juices from the pancreas and liver; jejunum is the second division where chemical digestion and absorption occurs; ileum is the third division where chemical digestion and absorption occurs
Enzymes secreted by the small intestine; aminopeptidase breaks down peptides into amino acids; maltase breaks down maltose into glucose units; lactase breaks down lactose into glucose and galactose; and sucrase breaks down sucrose into glucose and fructose
Accessory organ behind the stomach that produces pancreatic juice that enters the small intestine via the pancreatic duct; pancreatic juice contains bicarbonate ions (reduce acidity) and digestive enzymes
Amylase break down polysaccharides into disaccharides; trypsin and chymotrypsin break down proteins and polypeptides into smaller fragments; carboxypeptidase breaks down polypeptides into amino acids; lipase breaks down triglycerides into fatty acids and glycerol; and nucleases break down DNA or RNA into nucleotides
Liver produces bile; bile contains water, ions, cholesterol, and bile salts; bile emulsifies (breaks down) fat
Gallbladder stores bile; emulsification is the interaction of polar ends of fats with water to break them down; Chylomicrons contain the absorbed product of fat digestion, they are too big to enter the blood capillaries so they enter the lymphatic system
Where is most of the digestion occurring in the GI tract? The absorption?What structural features of the small intestine make it well suited for absorption? What are villi? What is a lacteal?
Most of the digestion occurs in the duodenum; most of the absorption takes place in the jejunum and ileum; wall of intestine is well suited for absorption because of its large amount of surface area created by folds, villi and microvilli; villi are fingerlike projections from the surface of the folds in the ling of the small intestine; lacteal are lymphatic capillaries in each villus that take up Chylomicrons
Cecum is a ouch that hangs below the junction of the small and large intestines; appendix extends from the cecum, has no digestive function; colon is the largest region of the large intestine composed of the ascending colon, the transverse colon, and the descending colon; rectum is where feces are pushed through; anal canal is where feces are released
What is, and where is, the ilealcecal valve?
Large intestine 1) absorbs most of the water remaining in the indigestible food residue, 2) stores feces, and 3) eliminates feces. Feces are waste material composed of undigested material, E. coli, water, and sloughed-off epithelial cells; bacteria in GI tract produce vitamins and break down undigested material
Rhythmic waves of muscular contraction and relaxation in the walls of digestive organs that push contents through the tubes
Feces are pushed into the rectum, stretching the rectal wall and initiating the defecation reflex. Nerve impulses from the stretch receptors in the rectal wall travel to the spinal cord, which sends motor impulses back to the rectal wall, stimulating muscles there to contract and propel feces to the anal canal. Internal sphincter relaxes automatically; external sphincter is under voluntary control.
How is salivation controlled? What happens when chewing with respect to regulation of the digestion? What happens when the stomach is stretched and there are partially digested proteins in the stomach? What is gastrin, where is it produced and what does it do?
Salivation is controlled by the nervous system; while chewing, the stomach secretes gastric juices and mucus; when the stomach stretches and there are partially digested proteins in the stomach, the lining of the stomach release gastrin; gastrin is a hormone released from the stomach that enters the blood stream, circulates throughout the body and increases the production of gastric juices
Acid chyme in the small intestine stimulates the release of several hormones; vasoactive peptide – releases enzymes; secretin – stimulates the release of sodium bicarbonate; cholocystokinin – releases enzymes in the pancreas and bile in the gallbladder
Composed of lymph, lymphatic vessels, and lymphoid tissues; functions: 1) uptake of excess interstitial fluid (return to blood) 2) absorption and transport of fat in the intestines 3) defend the body against disease
How does the lymphatic system take of excess interstitial fluid and return the fluid to the blood? How are lymph vessels similar to veins? How are lymphatic capillaries different than blood capillaries? What are the lymphoid tissues?
Lymph vessels take up fluid (lymph) which gets drained into the right lymphatic duct or the thoracic duct to be returned to the heart and the bloodstream; like veins, lymph vessels have a lot if valves for one-way direction but they are blind ended and more permeable than veins; lymphoid tissues contain lymphocytes (T and B cells) and are responsible for specific immune defenses
Chylomicrons (fat molecules) are too large to enter the blood capillaries so they enter the lacteal (lymphatic vessel) in the villi of the small intestine
The ability of the body to protect itself from infectious agents, foreign cells, and abnormal body cells (cancer cells)
What are tonsils and what do they do?
What are lymph nodes, what do they do, and where are they found?
What is the spleen and what is its role in immunity?
What is the Thymus gland, what is its function? What is thymosin?
What are the functions of the immune system?
What is a pathogen? What is an antigen?
What are the Physical and Chemical Barriers? What role do the skin, mucus membranes, sweat and oils, the stomach, urine, and saliva and tears play in this line of defense?
Prevent the entrance of anything into the internal environment; skin and mucus membranes are physical barriers; sweat and oils produced on the skin serve as chemical barriers; mucous membranes trap pathogenic organisms; stomach contains HCl and pepsin; urine is slightly acidic and flushes pathogenic organisms out of the urinary tract; saliva and tears contain Lysozyme that kill bacteria
Nonspecific: chemical and physical barriers, defensive cells (neutrophils, macrophages, eosinophils, natural killer cells), defensive proteins, inflammatory reaction, fever
Specific: B and T cells
What do B and T cells have to do with the specific immune defenses? How do B and T cells recognize antigens?
B and T cells have receptors for specific foreign molecules and bind to those molecules; effector cells are antibodies produced by B lymphocytes and released in the bodily fluid; memory cells recognize original antigen so that the next time it is present, they can destroy them faster
What are the two defining characteristics of the specific immune defenses and what do they mean? How is the specificity of the immune system determined?
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