4. Renal Physiology Flashcards
1
Q
Functions of the urinary system (4)
A
- excretion
- elimination
- homeostatic regulation of blood plasma
- maintain water and salt balance
2
Q
element that is removed when breaking down proteins and nucleic acids
A
nitrogen
3
Q
some of the most toxic byproducts from the breakdown of macromolecules (proteins and nucleic acid)
A
nitrogenous waste like NH3 (ammonia)
4
Q
how is ammonia lost/secreted in
- aquatic animals, including most bony fishes
- mammals, most amphibians, sharks, some bony fishes
- many reptiles (including birds), insects, land snails
an animals nitrogenous waste are correlated with its ________ and ________
A
- ammonia (soluble in water)
- urea (less toxic)
- uric acid (paste like form since less soluble)
an animals nitrogenous waste are correlated with its phylogeny and habitat
5
Q
urinary system includes (4)
A
- kidney
- ureter
- bladder
- urethra
6
Q
ureter conducts urine by ________ which is the involuntary contraction and relaxation of longitudinal and circular muscles throughout the digestive tract
A
peristalsis
7
Q
the reddish color of kidney is due to ______
A
rich blood supply
8
Q
kidney is
- located __________: lies between the dorsal wall (back) and the peritoneum (abdomen membrane)
- lies in the _______ and ______
- weighs _________
A
- retroperitoneally
- lies in the Thoracic 12 (T12) and Lumbar 5 (L5)
- weighs 150 g
9
Q
the two kidney is not in the same position
* _______ is more superior because of the presence of the liver in the other side
A
left kidney mas taas because of the liver that is pushing down the right kidney
10
Q
kidneys are supported with three layers of tissues
- transparent, strong barrier that prevents infection from spreading to kidney
- helps hold the kidneys in place
- dense and outermost connective tissue that helps adrenal glands and other organs to anchor from its surrounding
A
- renal capsule - transparent
- fat layer - adipose capsule
- fibrous tissue (Gerota’s fascia) - dense and outermost
11
Q
separate organ that sits in the top of kidney
A
adrenal gland
12
Q
where the blood vessels (renal pelvis) enter and exit
A
renal hilum/hilus
13
Q
Renal Pyramid
- _________ is the outermost layer in the internal structure
- _________ is middle layer, set of cone-shaped masses of tissue that secrete urine into tiny sac-like tubules
- _________ innermost, funnel-shaped tube surrounded by smooth muscle that uses peristalsis to move urine out of the kidney, into the ureter, and to the bladder
A
- renal cortex
- renal medulla
- renal pelvis
14
Q
renal pelvis branches to form ________ that subdivides further to form _________. These collects urine which drains from the medulla pyramids
A
major calyces
minor calyces
15
Q
carries unfiltered, oxygen rich blood to the kidney
A
renal artery
16
Q
carries filtered blood from the kidney to the inferior vena cava
A
renal vein
17
Q
in a _______ system, blood flows through two capillary networks: _________ and ________
A
portal system:
* glomerulus - first set of capillary beds
* peritubular capillaries
18
Q
Blood and Nerve Supply (8 only)
A
- aorta
- renal artery
- afferent arteriole
- glomerulus
- efferent arteriole
- peritubular capillaries
- renal vein
- inferior vena cava
19
Q
- the basic structural and functional unit of kidney in renal pyramid
- carry out the process that form urine
A
Nephron
20
Q
nephron can be categorized by:
A
- cortical nephron - 85%, short loop of Henle
- juxta-medullary nephron
21
Q
Parts of nephron (5)
A
- glomerulus
- bowman’s capsule
- proximal tubule
- loop of Henle
- distal tubule
22
Q
components of renal corpuscle (2)
A
- glomerulus
- bowman’s capsule
23
Q
renal tubule (3)
A
- proximal convoluted tubule (PCT)
- loop of Henle
- distal convoluted tubule (DCT)
24
Q
loop of Henle parts (2)
A
- descending limb
- ascending limb
25
receives urine from many nephron
collecting duct
26
highly specialized for filtration
glomerulus
27
each nephrons have a region of _________ is a specialized structure formed by **distal convoluted tubule** and **glomerular afferent arteriole**
juxtaglomerular apparatus (JGA)
28
the glomerular afferent arteriole have ______________ which are mechanoreceptors that sense blood pressure in the afferent arteriole
juxtaglomerular cells
29
are chemoreceptors or osmoreceptors present in DCT that responds to changes in solute content of the filtrate
Macula densa
30
functions of nephron (4)
* production of filtrate
* reabsorption of organic nutrients
* reabsorption of water and ions
* secretion of waste products into tubular fluid
31
**Glomerulus Anatomy**
the filtration membrane allows molecule
* smaller than ____ in diameter (**water, glucose, amino acids and nitrogenous waste**)
* larger than _____ = cannot pass (**proteins and red blood cells**)
* 3nm
* 7 nm
32
part of the glomerulus that is important for reclaiming and passing of salts
filtration slits
33
three characteristics of glomerulus
1. fenestration (pores) of glomerular capillaries
2. podocyte visceral layer
3. basement membrane
34
Basic Processes of Urine Formation: (3)
1. Glomerular filtration: blood -> filtrate
2. Tubular reabsorption (at PCT): filtrate -> blood
3. Tubular secretion (at DCT)
35
The fluid that enters the glomerular capsule is called ________ (because it is formed under pressure—the _______ of the blood.
ultrafiltrate
hydrostatic pressure
36
Forces that determine in glomerular filtration
* Glomerular (blood) hydrostatic pressure (favors filtration)
* Blood colloid osmotic pressure (against filtration) - particularly albumin
* Capsular hydrostatic pressure (against filtration)
37
pressure responsible for filtrate formation
Net Filtration Pressure (NFP)
NFP = HPg - (OPg + HPc)
38
* amount of filtrate produced in the kidney per minute
Glomerular Filtration Rate (GFR)
39
amount of filtrate produced in 1 day
180L/day
40
factors that alter filtration pressure change GFR (4)
* high BP (medication lower GFR)
* Sympathetic Activation (lower GFR)
* A drop in filtration pressure stimulates Juxtaglomerular apparatus (JGA)
* Release renin and erythropoietin (EPO)
41
changes in the diameter of the afferent arterioles result from (2)
1. extrinsic regulatory mechanisms
2. intrinsic regulatory mechanisms (renal autoregulation)
42
The cells of the **macula densa** are sensitive to the concentration of ___________ in the **distal convoluted tubule**.
sodium chloride
43
A decrease in sodium chloride concentration initiates a signal from the macula densa that has two effects:
* decrease arteriolar resistance, increase GFR
* increases **RENIN** release from the juxtaglomerular cells of the afferent and efferent arterioles
44
major storage sites for renin
juxtaglomerular cells of the afferent and efferent
arterioles
45
system that regulates blood pressure and volume
renin-angiotensin-aldosterone system (RAAS)
46
explain renin-angiotensin-aldosterone system (RAAS)
* juxtaglomerular cells produces renin when blood pressure is low
* renin (from kidney) cleaves **angiotensin I** from **angiotensinogen**
* endothelial cells make **Angiotensin Converting Enzyme** (ACE) which converts angiotensin 1 to **angiotensin II**
* angiotensin II binds to receptors on afferent and efferent arterioles causing the **arterioles to constrict**
* lower arteriole resistance, increased renal blood flow (GFR)
* **to maintain GFR** : efferent arterioles are more receptive to angiotensin II than afferent arterioles
* low angiotensin II: blood remain in glomerulus when (GFR preserved)
* high angiotensin II : both afferent and efferent constrict, lower blood flow and GFR
47
intrinsic mechanism to maintain blood pressure (2)
* myogenic mechanism
* tubuloglomerular mechanism
48
reflex of smooth muscle cells to contract when stretched and causes **vasoconstriction of afferent and efferent arteriole**
myogenic mechanism
49
mechanism when macula densa senses high Na and Cl concentration which prompts vasoactive chemical (adenosine) that causes **vasoconstriction of afferent and efferent arteriole**
tubuloglomerular mechanism
50
two types of extrinsic mechanism
* hormonal (renin-angiotensin) mechanisms
* neural controls
51
in _______, baroreceptors in blood vessels of systemic circulation relays information to the sympathetic nervous system causing vasoconstriction of arteriole
neural controls
52
angiotensin II (by liver) also releases _____ in the *adrenal gland* and ______ made by *hypothalamus* and released by the posterior pituitary
* aldosterone
* ADH
53
which **increases Na+ and water reabsorption** when the renal blood pressure is low
aldosterone
54
hormone that
* mediates insertion of aquaporins intro nephron collecting duct cells; as a result, more water is reabsorbed into the blood
* increases Na+ reabsorption
ADH
55
is a hormone made in *atrial cells in the heart* which is antagonistic to the angiotensin pathway which increase GFR by **decreasing Na+ reabsorption** and **inhibiting the release of renin, aldosterone, and ADH**
ANP (Atrial Natriuretic Peptide) or ANF (Atrial Natriuretic factor)
56
**tubular reabsoprtion**
in pct, what molecules are being excreted (4) and absorbed (3)
the pct excretes: (back to the blood)
- NaCl
- H2O
- K+
- Nutrients
and absorbs (blood to filtrate):
- H+
- NH3
- K+
57
what part reabsorbs the water and NaCl from the filtrate to the blood and after this conditional reabsorption of Na+ and water takes place in ________?
loop of henle
DCT
58
is important for:
1. Disposing substances not already in the filtrate such as drugs, toxins
2. Eliminating undesirable substances that have been reabsorbed by passive processes like urea and uric acid
3. Ridding the body excessive potassium ions
4. Controlling blood pH
Tubular Secretion
59
Countercurrent Multiplication
**Countercurrent flow (flow in opposite directions) in the ascending and descending limbs** and the close proximity of the two limbs allow for interaction between them. Since the concentration of
the tubular fluid in the descending limb reflects the concentration of surrounding interstitial fluid, and since the concentration of this fluid is raised by the active extrusion of salt from the ascending limb, a **positive feedback mechanism** is created.
The **more salt the ascending limb** extrudes, the **more concentrated will be the fluid that is delivered to it from the descending limb**. This positive feedback mechanism multiplies the concentration of interstitial fluid and descending limb fluid, and is thus called the ______________.
countercurrent multiplier system
60
hormone primarily responsible for producing urine and regulating water balance
- an antidiuretic is any chemical that prevents excessive urine production
- without this, urine flow could be increased to 25 liters per day
Antidiuretic hormone (ADH)
