Homeostasis/kidneys

Front 1

proximal convoluted tubule

Back 1

portion of the duct system of the nephron leading from Bowman's capsule to the loop of Henle.

brush border increases surface area

lots of mitochondria supply energy to pump out Na+

Front 2

distal convoluted tubule

Back 2

between the loop of Henle and the collecting duct system.

H+/HCO3- antiport in both directions

secretes K+, absorbs Na+

reabsorbs Ca++ in response to parathyroid hormone

Front 3

atrial natriuretic protein

Back 3

powerful vasodilator, and a protein hormone secreted by heart muscle cells.It is involved in the homeostatic control of body water, sodium, potassium and fat.

opposes RAAS by inhibiting release of renin from JGA

in response to high blood pressure. ANP acts to reduce the water, sodium and adipose loads on the circulatory system, thereby reducing blood pressure

Dilates the afferent glomerular arteriole, constricts the efferent glomerular arteriole, and relaxes the mesangial cells. This increases pressure in the glomerular capillaries, thus increasing the glomerular filtration rate (GFR), resulting in greater excretion of sodium and water.

Front 4

collecting duct

Back 4

ubules and ducts that connect the nephrons to the ureter. It participates in electrolyte and fluid balance through reabsorption and excretion, processes regulated by the hormones aldosterone and antidiuretic hormone.

* In the absence of ADH, water in the renal filtrate is left alone to enter the urine, promoting diuresis.
* When ADH is present, aquaporins allow for the reabsorption of this water, thereby inhibiting diuresis.

Front 5

podocytes

Back 5

cells in the Bowman's capsule that wrap around the capillaries of the glomerulus

separated by filtration slits that form filtration membrane that take in filtrate

Front 6

Bowman's capsule

Back 6

cup-like sac at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine

wraps around glomerulus; receives filtrate via slits between podocytes

Front 7

afferent arteriole

Back 7

branch from the renal artery which supplies blood to the kidneys.

-later diverge into the capillaries of the glomerulus.

-when hypotensive, releases renin to raise BP

Front 8

efferent arteriole

Back 8

form from a convergence of the capillaries of the glomerulus.

play an important role in maintaining the glomerular filtration rate despite fluctuations in blood pressure.

note that juxtomedullary artioles

Front 9

loop of Henle

Back 9

leads from the proximal straight tubule to the distal convoluted tubule. The loop has a hairpin bend in the renal medulla

-main function is to create a concentration gradient in the medulla of the kidney

descending: permeable to H20, not v. permeable to ions/urea

ascending: permeable to ions, not H2O

thin medullary (ascending): NaCl passively out into medulla, water follows

thick medullary: NaCl pumped out of tube, water follows

K+ pumped into tube, allowing more Na+ to flow out, water follows

Front 10

peritubular capillaries

Back 10

btw efferent arterioles and small veins

-receive materials returned to blood by renal tubules

Front 11

vasa recta

Back 11

descending portion: NaCl and urea are reabsorbed into the blood, while water is secreted

ascending portion: NaCl and urea are secreted into the interstitium, while water is reabsorbed.

Front 12

nonshivering thermogenesis

Back 12

brown fat of infants and hibernating mammals

substances such as free fatty acids remove purine (ADP, GDP and others) inhibition of thermogenin (uncoupling protein-1), which causes an influx of H+ into the matrix of the mitochondria and bypasses the ATP synthase channel. This uncouples oxidative phosphorylation, and the energy from the proton motive force is dissipated as heat rather than producing ATP from ADP.

Front 13

convection

Back 13

movement of molecules within fluids

heat transfer through fluids

Front 14

glomerulus

Back 14

capillary tuft that performs the first step in filtering blood to form urine

surrounded by Bowmans

receives blood from afferent arterioles

small passage of afferent arteriole makes for high pressure in glom, allowing for easier filtration

Front 15

aldosterone

Back 15

steroid hormone secreted by adrenal cortex in response to low BP and angiotensin II

-stimulates DCT and collecting tube to reabsorb more Na+

-increases blood volume and BP

Front 16

cortical nephrons

Back 16

corpuscle starts more superficially (higher) in cortex

Front 17

osmoreceptor cells

Back 17

sensory receptor primarily found in the hypothalamus of most homeothermic organisms that detects changes in osmotic pressure

Front 18

vasodilation

Back 18

widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins

Front 19

antidiuretic hormone (ADH)

Back 19

-peptide hormone
-produced in hypothalamus
-released by posterior pituitary
-makes collecting tube more permeable to water, allowing more water to be reabsorbed
-increases BP
-negative feedback loop

Front 20

juxtaglomerular apparatus

Back 20

-small group of cells where renal tubule contact afferent and efferent arterioles
-regulate nephron function by secreting renin when BP falls
-activates renin-angiotensin-aldosterone pathway

Front 21

angiotensin

Back 21

-renin in blood activates angiotensinogen to angiotensin I
-ACE converts I to II
-II constricts arterioles, raising BP
-also signals adrenal glands to release aldosterone

Front 22

fenestra

Back 22

small pores in endothelial cells to allow for rapid exchange of molecules between blood vessels and surrounding tissue

Front 23

paracrine regulation

Back 23

signal acts on nearby cells

Front 24

prostaglandins

Back 24

paracrine regulators that modify cAMP levels and interact with other signaling molecules
-cause fever, swelling, pain

Front 25

Inositol triphosphate & diacylglycerol & phospholipase C

Back 25

Gq protein stimulates PLC to separate another membrane phospholipid into IP3 and DAG.
-IP3 stimulates release of Ca++ from ER
-DAG phosphorylates target enzymes directly

Front 26

vasopressin

Back 26

aka ADH; enhances permeability of collecting duct to water

Front 27

oxytocin

Back 27

-made in hypothalamus
-secreted from posterior pituitary
-lactation-
-pair bond from sex and childbirth

Front 28

hypothalamus

Back 28

portion of the brain that links to endocrine system
-portal axis to pituitary
-makes ADH and oxytocin for posterior
-makes and secretes releasing and inhibiting hormones that regulate release of hormones from anterior pituitary

Front 29

posterior pituitary

Back 29

-neuroendocrine organ that releases oxytocin and ADH

Front 30

anterior pituitary

Back 30

-cellularly epithelial
-receives hormonal signals from hypothalamus to release all sorts of hormones for growth and tropic control of other glands
--GH
--prolactin
--melanocyte stimulating hormone
-thyroid stim horm
-adrenocorticotropic hormone
-LH and FSH

Front 31

thyroid gland

Back 31

releases T4 and T3 (more active form), which effect many metabolic processes
-regulated by release of TSH from anterior pituitary (negative feedback)

-calcitonin inhibits release of Ca++ from bone when Ca levels high

Front 32

parathyroid glands

Back 32

embedded in CT surrounding thyroid

-release parathyroid hormone, a calcitonin antagonist
--acts by way of G protein and cAMP to release Ca++ from bones and kidney tubules

Front 33

pancreas

Back 33

alpha cells secrete insulin: storage; lowers [glucose]

beta cells secrete glucagon: converts glycogen to glucose.
-breaks down fats

Front 34

islets of langerhans

Back 34

islets of alpha and beta cells in the pancreas

Front 35

adrenal medulla

Back 35

neuroendocrine gland coupled to sympathetic NS.
-secretes NE as a reaction to stress

Front 36

hypothalamus role in thermoregulation

Back 36

if hot:
1. message to dilate skin blood vessels --> heat radiates from skin
2. sweat

if cold:
1. constrict blood vessels
2. skeletal muscle shivering