PhysiologyTest 2 Flashcards
define antigen presentation
antigen presentation occurs when an antigen glycoprotein combination capable of activating T cells, appears in a plasma membrane. T cells sensitive to this antigen are activated if they contact the antigen on the plasma membrane of the antigen presenting cell
identify the 3 major types of T cells activated by class 1 MHC proteins
the 3 major types of t cells activated by class 1 MHC proteins are:
cytotoxic T cells
memory T cells
suppressor T cells
describe CD markers
T cell plasma membranes contain proteins called CD (cluster of differentiation) markers. cells with CD8 markers respond to antigens presented by class 1 MHC proteins and are on cytotoxic t cells. memory T cells and suppressor T cells with CD4 makers respond to class 2 MHC proteins
how can the presence of an abnormal antigen in the cytoplasm of a cell initiate an immune response
abnormal antigens in the cytoplasm of the cell can become attached to MCH proteins and displayed on the surface of plasma membrane. the recognition of such antigens by T cells initiate an immune response
define sensitization
sensitization is the process by which a B cell prepares to undergo activation so that it can subsequently react with a specific antigen
explain the function of cytokines secreted by helper T cells
cytokines secreted by activated T cells aid in coordinated specific and nonspecific defense and regulate cell mediated antibody mediated immunity
if you observe a higher than normal number of plasma cells in a sample of lymph would you expect antibody levels in the blood to be higher or lower than normal
plasma cells produce and secrete antibodies so observing an elevated number of plasma cells in the lymph would lead to expect higher than normal antibody levels in the blood
define allergy and allergen
an allergy is an inappropriate or excessive immune response to an allergen. an allergen is an antigen that triggers an allergic reaction
what is the anaphylaxis
in anaphylaxis an immune response to a circulating antigen stimulate mast cells throughout the body to release chemicals that prompt the inflammatory response
which chemicals do mast cels and basophils release when stimulated in an allergic reaction
histamines, leukotrienes, and other chemicals that cause pain, and inflammation are released when mast cells and basophils are stimulated in an allergic reaction
define Dalton’s law
Dalton’s law states that the in a mixture of gases. the individual gases exert a pressure proportional to their abundance in the mixture
what is the significance of Henry’s law to the process of respiration
Henry’s law states that, at a given T, the amount of a particular gas that dissolves in a liquid is directly proportional to the partial pressure of that gas. Henry’s law underlies the diffusion of gases between capillaries and alveoli, and between capillaries and interstitial fluid
define oxyhemoglobin
hemoglobin to which oxygen molecules have bound
explain the relationship among BPG, OXYGEN, AND HEMOGLOBIN
BPG is a compound that reduces hemoglobin’s affinity for oxygen. for any partial pressure of oxygen, if the concentration of BPG increase, the amount of oxygen released by hemoglobin will increase
during exercise, hemoglobin releases more oxygen to active skeletal muscles than it does when those muscles are at rest. why?
the combination of increased T and lower pH causes hemoglobin to release more oxygen that when the muscles are at rest. There is a lower pH because there is heat and acidic waste products generated by active skeletal muscles
normal interstitial fluid has a PO of what
40 mm Hg
define hemoglobin
molecule consisting of four globular protein subunits, each containing a heme unit. can reversibly bind up to four molecules of oxygen
what is CO and why can it be bad
gas released by petroleum-burning engines and heaters. it will irreversibly bind to units, making them unavailable for oxygen transport
what is hemoglobin saturation
the percentage of heme units containing bound oxygen at any given moment
RBCs do not contain mitochondria, so they can only generate ATP though what
glycolysis
RBCs do not contain mitochondria, so they can only generate ATP though what
glycolysis
the metabolic pathways involved in glycolysis also generate what
BPG
the metabolic pathways involved in glycolysis also generate what
BPG
the higher the concentration of BPG the ___ oxygen will be released by the Hb molecules
more
the higher the concentration of BPG the ___ oxygen will be released by the Hb molecules
more
BPG production — as RBCs age
decrease
BPG production — as RBCs age
decrease
name the five major hormones that regulate digestive activities
gastrin secretin gastric inhibitory peptide (GIP) cholecystokinin (CKK) vasoactive intestinal peptide (VIP)
does a high fat meal raise or lower the level of cholecystokinin (CKK) in the blood
raises the level in the blood
how would the pH of the intestinal contents be affected if the small intestine did not produce secretin
if the small intestine did not secrete secretin, the pH of the intestinal contents would be lower (more acidic) than normal, because secretin stimulates the pancreas to release a fluid high in buffers that neutralizes the acidic chyme entering the duodenum from the stomach
name and describe an important characteristic of each of the 3 overlapping phases of gastric secretion
cephalic phase==which prepares the stomach to receive ingested materials
the gastric phase==begins with the arrival of food in the stomach
intestinal phase==controls the rate of gastric emptying
describe two central reflexes triggered by stimulation of the stretch receptors in the stomach wall
gastroenteric reflex==stimulates motility and secretion along the entire small intestine gastroileal reflex==triggers the opening of the ileocecal valve to allow passage of materials from the small intestine into the large intestine
why might severing the branches of the vagus nerves that supply the stomach provide relief for a person who suffers from chronic gastric ulcers
it would interrupt parasympathetic stimulation of gastric secretions, and the consequent reduction in acid secretions would provide some relief
define hemorrhoids
distended, swollen veins in the distal portion of the rectum that may result from straining
compare the structural features of the large intestine and the small intestine
the large intestine is larger in diameter and shorter in length. it’s relatively thin wall lacks villi and has an abundance of mucous cells and distinctive intestinal glands
describe the two positive feedback loops involved in the defecation reflex
short reflex=stretch receptors in the rectal walls promote a series of peristaltic contraction in the colon and the rectum, moving feces into the anal canal
long reflex==parasympathetic motor neurons in the sacral spinal cord, also activated by the stretch receptors stimulate peristalsis via motor commands distributed by somatic motor neurons
name the lobes of the liver
left
right
caudate
quadrate
what is the function of the gallbladder
temporarily stores bile produced by the liver
what structure marks the division between the left lobe and right lobe of the liver
the falciform ligament marks the division between the left lobe and the right lobe of the liver
define hepatocyte
a liver cell
describe a portal area
located at each of the six corners of a liver lobule; each portal area contains:
- a branch of the hepatic portal vein
- branch of the hepatic artery
- small branch of the bile duct
define Kupffer cells, and indicate their functions
liver macrophages that engulf pathogens, cell debris, and damaged blood cells
define emulsification
the breakdown of lipid droplets by bile salts
what are the primary digestive functions of the gallbladder and pancreas
stores and releases bile, which contains additional buffers and bile salts that facilitate the digestion and absorption of lipids. the pancreas provides several digestive enzymes necessary for the breakdown of starches, lipids, nucleic acids, and proteins
trace a drop of bile from the hepatic ducts to the duodenal lumen
hepatic ducts–>common hepatic duct–>common bile duct–>duodenal ampulla and papilla–>duodenal lumen
can the permeability of the PCT or DCT ever change? why or why not
No, the permeability of the PCT cannot change, and water reabsorption occurs whenever the osmotic concentration of the peritubular fluid exceeds that of the tubular fluid
what effect does an increase in ADH levels have on the DCT
increased ADH levels cause the appearance of more water channels, or aquaporins, in the DCT; as a result, more water is reabsorbed into the peritubular fluid, which reduces the volume of water in the urine
when ADH levels in the DCT decrease, what happens to the urine osmotic concentration
decreased ADH levels in the DCT reduce the urine osmotic concentration due to the presence of more water in the urine; the result is a larger volume of more dilute urine
define dialysis
process of using an artificial semipermeable membrane to remove waste products from the blood of a person whose kidneys are not functioning properly
briefly explain the difference between chronic renal failure and acute renal failure
chronic-involves a gradual loss of renal function
acute-involves a sudden loss of renal function
explain why patients on dialysis often receive Epogen or Procrit, and synthetic form of erythropoietin
pts on dialysis are often given a synthetic form of erythropoietin to treat anemia, which occurs because their malfunctioning kidneys produce too little erythropoietin, the hormone that stimulates the development of RBCs in the bone marrow
urine is transported by the __, stored within the __, and eliminated through the ___
urine is transported by the ureters, stored within the bladder, and eliminated through the urethra
the wall of the urinary bladder is composed of a specialized smooth muscle. name it and describe its physiological role
specialized smooth muscle in the wall of the bladder is the detrusor muscle, its contraction compresses the bladder and expels urine into the urethra
what has to happen to the external urethral sphincter to allow urination
external urethral sphincter must be consciously relaxed to allow urination
what is the term for painful or difficult urination
dysuria
obstruction of a ureter by a kidney stone would interfere with the flow of urine between which two points
between the kidney and the bladder
why is urinary obstruction at the urethra more dangerous than at the ureter
urinary obstruction at the urethra is more dangerous than urinary obstruction in the ureter because urine would be prevented from exiting the body and would build up in the bladder, leading to rupture. obstruction of only one of the two ureters is less hazardous than obstruction of the lone urethra because in the former case, the other kidney would sill excrete wastes that could be voided
the sensation of a full bladder is relayed from the bladder to the thalamus to the ___
cerebral cortex
voluntary relaxation of the external urethral sphincter cause relaxation of the internal urethral sphincter via what mechanism
micturition reflex
describe the micturition reflex
the urge to urinate usually appears when the urinary bladder contains about 200 mL of urine. the micturition reflex begins to function when the stretch receptors have provided adequate stimulation to the parasympathetic motor neurons. the activity in the motor neurons generates action potentials that reach the smooth muscle in the wall of the urinary bladder. these efferent impulses travel over the pelvic nerves, producing a sustained contraction of the urinary bladder
