Unit 6 Urine and Acid Base System Flashcards
Major Functions
- Excretion of waste products from blood
- Convservation of blood nutrients
- regulation of blood ion levels
- Regulation of blood pH
- Regulation of blood volume, BP
- Production of hormones into the blood
Glomerular hydrostatic P
GHP - 50 mmHg
- pushes water and small solutes out via fenestrated capillaries and filtration slits
Capsular hydrostatic P
CsHP - 15 mmHg
- pushes water and small solutes back into the blood
Net hydrostatic P
NHP: GHP-CsHP
50 - 13 = 35
Blood colloid osmotic P
BCOP - 25 mmHg
- pulls the water back into the blood it opposes filtration
Filtration P
FP: NHP - BCOP
35 - 25 = 10
Creatine clearance rate
decent index used ?????
ANP - Hormones
BNP - Hormones
Atria natriuretic peptides - released by atria of heart
Brain natriuretic peptide - released by ventricles of heart
- released when increased blood volume or blood pressure stretches the wall of the heart
- increase in stretch leads to afferent VD& efferent VC which leads to increase in GFR
- also leads to a decrease in Na+ reabsorption which leads to increase loss of Na+ and H2O
Renin-andiotensin-aldosterone RAA
Renin is released from the juxtaglomerular complex which in turn increases GFR
Hormone
a compound that is secreted by one cell and that travels through he blood stream to affect the activities of cells in another portion of the body
enzyme
a protein that catalyzes a specific biochemical reaction
Three things that trigger the release of renin
- Low glomerular BP
- SNS stimulation of juxtaglomerulus cells
- Low osmolarity at macula dense
Angiotensinogen
renin converts the inactive protein antiotensinogen to AT1; AT1 is also inactive but is then converted to angiotensin 2 by converting enzyme called ACE (conversion takes place in capillaries of the lungs
AT2
triggers increased aldosterone (ALDO) secretion by the adrenal glands with increases Na+ retention
-efferent VC, thirst, SNS, ADH (anti-diurectic hormone) makes you not pee so you can retain water.
Cotransport
both in the same direction; follows the gradient for 1 solute
Countertransport
follows the gradient for 1 solute; solutes travel in opposite directions
-specific, unidirectional, variable distribution, heterogenous distribution, saturable
Transport maximum (Tm)
substance the saturates carrier capacity - highest load you can handle and absorb
Renal threshold
plasma gradient at which compound starts to appear in the urine; varies by compound
countercurrent
exchange occurs between fluids moving in opposite directions - occurs in the loop of henle
- significant reabsorption of remaining water Na+, CL-
multiplier
effect of exchange amplified as fluid movement continues - occurs in the loop of hence
- significant reabsorption of remaining water Na+, CL-
2 Major benefits of countercurrent multiplier system
- efficiently reabsorbs solutes, water before fluid reaches DCT, collecting ducts
- establishes [ ] gradient that permits passive reabsorption of water from collecting ducts
Anti - diuretic hormone (ADH)
From pituitary gland
- stimulates aquaporin production
- permits/promotes water reabsorption
- low levels of ADH at normal rest
Dehydration increases ADH secretion - absorb lots of water
EtOH inhibits ADH secretion - you dehydrate quickly
aquaporin
water channels
