Phys Exam 4

Please get me an A

nephron

function unit of the kidney, which begins at Bowman’s capsule

cortex

outer portion of the kidney

medulla

inner portion of the kidney

renal arteries

blood vessels that take blood to the cortex

renal corpuscle

segment of the nephron made up of the glomerulus and Bowman’s capsule that functions to filter mostly protein-free plasma from the capillaries into the capsule

proximal tubule

segment of the nephron that functions in isosmotic reabsorption of organic nutrients, ions, and water and secretion of metabolites and xenobiotic materials such as penicillin; site of reabsorption for filtered bicarbonate

loop of Henle

segment of the nephron that functions in reabsorption of ions in excess of water to create dilute fluid in the lumen; countercurrent arrangements contributes to concentrated interstitial fluid in the renal medulla; location of the majority of water reabsorption in the kidneys

distal nephron

segment of the nephron made up of the distal tubule and the collecting duct that functions in regulated reabsorption of ions and water for salt and water balance and pH homeostasis

glomerular filtration rate

measurement of how fast material moves from the plasma to the urine

afferent arteriole

blood vessel that delivers blood to the glomerulus

efferent arteriole

blood vessel that carries blood away from the glomerulus

20%

what percentage of plasma that passes through the glomerulus is filtered?

1%

what percent of filtered fluid is eventually excreted?

net filtration pressure

capillary hydrostatic pressure - (Bowman’s hydrostatic pressure + plasma colloid osmotic pressure)

capillary hydrostatic pressure

pressure that forces fluid out of the glomerulus into the capsule

Bowman’s hydrostatic pressure

pressure that pushes fluid out of the capsule back into the glomerulus

plasma colloid osmotic pressure

pressure that draws fluid into the glomerulus based on the presence of plasma solutes

myogenic mechanism

autoregulation mechanism in which hypertension causes afferent stretching → reflexive contraction → reduced blood flow → reduced GFR

tubuloglomerular feedback

autoregulation mechanism in which high flow → less nitric oxide (NO) release → no dilation signal → vasoconstriction

norepinephrine

neurotransmitter that causes afferent vasoconstriction via that alpha-1 receptor

vasoconstriction

process of the afferent arteriole that decrease GFR and increases BP

urinalysis

measure of glucose, bilirubin, ketones, specific gravity, blood, pH, protein, urobilinogen, nitrite, and leukocytes as a sign of disease

transcellular

form of transport in which solutes and water move into and then out of epithelial cells

paracellular

form of transport in which solutes move through junctions between epithelial cells

SGLT

sodium moving down its electrochemical gradient uses ______ protein to pull glucose into the cell against its concentration gradient

basolateral

glucose diffuses out of the ________ side of a cell using the GLUT protein

excretion

filtration - reabsorption

splay

difference between urine threshold and saturation

primary active transport

the Na+-K+-ATPase keeps intracellular [Na+] low

secondary active transport

the Na+-dicarboxylate cotransporter (NaDC) concentrates a dicarboxylate inside the cell using energy stored in the [Na+] gradient

tertiary active transport

the basolateral organic anion transporters (OAT1-3) concentrate organic anions (OA-) inside the cell, using the energy stored in the dicarboxylate gradient

dicarboxylate

organic ions enter the lumen of the cell in exchange for this molecule

penicillin

medication cleared from plasma and into the urine at a high rate; about 80% of a dose is cleared within 3-4 hours of administration

inulin

inert plant polysaccharide that is filtered but not secreted or reabsorbed; clearance of this molecule is equal to GFR

PAH

medicine used to determine kidney function; competes for penicillin transporters during secretion; secreted in the proximal tubule and 500% net excreted

sodium and calcium

solutes that are reabsorbed in the proximal tubule, reabsorbed in the ascending limb of the loop of Henle, regulated absorption in the distal nephron, and 1% net excreted (each)

potassium

solute that is reabsorbed in the proximal tubule, reabsorbed in the ascending limb of the loop of Henle, reabsorbed in the distal nephron, and 2% net excreted if low, 10-20% net excreted if normal, and up to 150% net excreted if high intake

glucose

solute that is 100% reabsorbed in the proximal tubules (0% excreted)

urea

solute that is reabsorbed in the proximal tubule, secreted in the ascending limb of the loop of Henle, reabsorbed in the distal nephron, and 30-50% net excreted

clearance

rate at which material is removed from the blood and appears in urine

renal plasma clearance

(concentration of substance in urine x urine flow)/ (concentration of substance in plasma)

micturition

release of urine that requires both smooth and skeletal muscle and parasympathetic innervation; spinal reflex subject to higher brain control; triggered by stretch receptors

internal

urinary sphincter made of smooth muscle that stays passively contracted

external

urinary sphincter made of skeletal muscle that stays contracted due to the tonic firing of a motor neuron

loop diuretics

medications that lower blood pressure by increasing water loss in the loop of Henle

vasa recta

blood vessels of the nephron that act in countercurrent exchange by running in the opposite direction of the loop of Henle; contain blood that removes water leaving the loop

vasopressin (ADH)

hormone released by the posterior pituitary to increase water retention and blood pressure by inserting aquaporin channels in the collecting duct

aldosterone

hormone released by the adrenal cortex that increases blood pressure by the reabsorption of sodium and secretion of potassium in the tubule

juxtaglomerular apparatus

little ball of cells in afferent arterioles near the kidney that notices when osmolarity goes up or blood volume goes down and secretes renin in response

renin

enzyme that converts angiotensinogen produced by the liver to convert to angiotensin I

ACE

enzyme from the lungs that converts angiotensin I to angiotensin II

ACE inhibitors

medications that lower blood pressure by stopping angiotensin II from being made, which makes aldosterone levels go down, which stops blood pressure from being raised

atrial natriuretic peptide

hormone that is released from myocardial cells when the heart is overstretched, promoting salt and water excretion to decrease blood pressure

reduced hemoglobin

most common protein buffer in plasma

type A

intercalated cells in the collecting duct that function in acidosis by excreting H+ and reabsorbing HCO3- and K+

type B

intercalated cells in the collecting duct that function in alkalosis by excreting HCO3- and K+ and reabsorbing H+

bile

chemical that emulsifies fats and allows them to travel into plasma; produced by the liver and stored in the gallbladder

pancreas

organ with endocrine (producing hormones) and exocrine (producing digestive enzymes) functions

gallbladder

organ that stores bile

secretion

basic process of digestive system involving movement of materials from cells into lumen or extracellular fluid

digestion

basic process of digestive system involving chemical and mechanical breakdown of food into absorbable units

absorption

basic process of digestive system involving movement of material from gastrointestinal lumen to extracellular fluid

motility

basic process of digestive system involving involving movement through the gastrointestinal tract as a result of muscle contraction

peristalsis

smooth muscle layers move food through the GI tract

villi

fingerlike projections of the small intestine that enhance surface area

mucosa

inner lining of the intestinal tract with three sublayers and paracellular transport; contains GALT (Peyer’s patches)

submucosa

middle lining of the intestinal tract, containing blood, lymph, and nerve

plexus

nerve network in the small intestine

muscularis externa

circular and longitudinal muscle layers of the intestinal tract, working in opposite directions

serosa

outer lining of the intestinal tract; made up of connective tissue and epithelium

long reflexes

control of digestive muscle control integrated in the CNS

short reflexes

control of digestive muscle control originating in the enteric nervous system and carried out entirely within the wall of the gut

gastrin

hormon that stimulates secretion of gastric acid into the stomach

secretin

hormone that stimulates the secretion of pancreatic fluid

CCK

hormone that stimulates the secretion of bile and pancreatic enzymes and promotes satiety

cephalic

phase of food processing that prepares the stomach for the arrival of food

salivary amylase

enzyme that breaks down carbohydrates in the mouth

2.1

natural pH of the stomach

alkaline tide

temporary increase in blood pH as H+ is released into the stomach and HCO3- into interstitium during digestion

mucus-bicarbonate barrier

mucus layer acts as a physical barrier and bicarbonate is a chemical barrier that neutralizes acid

surface cells

cells that secrete mucus, which is a physical barrier between lumen and epithelium

neck cells

cells that secrete bicarbonate, which buffers gastric acid to prevent damage to the epithelium

parietal cells

cells that secrete gastric acid and intrinsic factor

gastric acid

HCl; chemical that activates pepsin and kills bacteria

intrinsic factor

chemical that complexes with vitamin B12 to permit absorption

enterochromaffin-like cells

cells that secrete histamine, which stimulates gastric acid secretion

chief cells

cells that secrete pepsinogen, which digests proteins, and gastric lipase, which digests fats

D cells

cells which secrete somatostatins

somatostatin

hormone that inhibits gastric acid secretion

G cells

cells that secrete gastrin

gastric alcohol dehydrogenase

enzyme that begins the breakdown of ethanol; typically less efficient in women

common hepatic duct

vessel that takes bile made in the liver to the gallbladder for storage

common bile duct

vessel that takes bile from the gallbladder to the lumen of the small intestine

hepatic artery

vessel that brings oxygenated blood containing metabolites from peripheral tissues to the liver

hepatic portal vein

vessel in which blood leaves the liver; contains blood rich in absorbed nutrients from the gastrointestinal tract and contains hemoglobin breakdown products from the spleen

sphincter of Oddi

muscle that controls release of bile and pancreatic secretions into the duodenum

islet cells

pancreatic cells that secrete hormones that enter the blood

acinar cells

pancreatic cells that form the exocrine portion and secrete digestive enzymes

duct cells

pancreatic cells that secrete NaHCO3 that enters the digestive tract

trypsin

enzyme activated by brush border enteropeptidase that activates other pancreatic enzymes