Kidneys Flashcards by Annie Yen

Parts of the excretory system:

2 kidneys
2 ureters
urinary bladder
urethra

How well did you know this?

Not at all

Perfectly

Functions of kidneys:

excrete wastes as urine
homeostasis of body fluid and blood volume
electrolyte balance
balance pH
produce and secrete hormones and vasoactive substances

How well did you know this?

Not at all

Perfectly

Where are the kidneys located?

retroperitoneal: on posterior wall of abdomen behind peritoneum

How well did you know this?

Not at all

Perfectly

Function of ureters:

1 in each kidney

- transports urine from renal pelvis into urinary bladder via peristaltic contractions induced by stretching of ureters

How well did you know this?

Not at all

Perfectly

Ureters have what kind of muscles and is under what kind of control?

smooth muscles

- myogenic control

How well did you know this?

Not at all

Perfectly

Structure of urinary bladder:

layers of smooth muscle surround transitional epithelium lining and has an internal sphincter

muscles are stretch activated and produces spontaneous APs
not under conscious control

How well did you know this?

Not at all

Perfectly

How do PNS fibers affect urinary bladder?

causes sustained contractions of the smooth muscles

- promotes emptying

How well did you know this?

Not at all

Perfectly

Function of urinary bladder:

stores urine until micturition (pee)

- empties into urethra

How well did you know this?

Not at all

Perfectly

How do SNS fibers affect urinary bladder?

causes contraction of internal sphincter

- prevents emptying

How well did you know this?

Not at all

Perfectly

The urethra passes through…

the urogenital diaphragm

How well did you know this?

Not at all

Perfectly

Structure of urethra:

skeletal muscle forms external sphincter

- under voluntary control

How well did you know this?

Not at all

Perfectly

Examples of waste products:

metabolites
end products of hemoglobin and hormone metabolism
drugs
pesticides
toxins

How well did you know this?

Not at all

Perfectly

Examples of metabolites:

urea (byproduct of aminio acid)
uric acid (byproduct of nucleic acid)
creatinine (byproduct of muscle)

How well did you know this?

Not at all

Perfectly

How do the kidneys regulate homeostasis of body fluids?

via regulation of water and NaCl excretion

How well did you know this?

Not at all

Perfectly

How do the kidneys balance pH?

maintained via plasma buffers

- aided by actions of lungs, liver, and kidney

How well did you know this?

Not at all

Perfectly

What hormones do the kidneys secrete?

erythropoietin
renin
calcitriol
prostaglandins and thromboxane

How well did you know this?

Not at all

Perfectly

Function of erythropoietin:

in response to low O2 to stimulate RBC production

- eventually increases O2 level

How well did you know this?

Not at all

Perfectly

Function of renin:

in response to low BP to activate angiotensin (vasoconstrictor)
- activates aldosterone to increase Na+ retention -> increase blood volume -> increase blood pressure

How well did you know this?

Not at all

Perfectly

Function of prostaglandins and thromboxane:

vasoactive products that act locally

afferent arteriole vasodilation
increase in Na+ and H2O secretion

How well did you know this?

Not at all

Perfectly

Function of calcitriol:

increases intestinal Ca2+ absorption and deposition into bone

How well did you know this?

Not at all

Perfectly

Function of NSAIDs on kidneys:

block COX 1 and 2 (prostaglandins)

Na+ and H2O retention
hypertension
hemodynamic acute kidney injury

How well did you know this?

Not at all

Perfectly

What is the hilum of the kidney?

indentation on surface of kidney

where blood vessels and nerves enter and exit kidney
where ureter leaves kidney

How well did you know this?

Not at all

Perfectly

Kidney is surrounded by…

dense CT capsule

How well did you know this?

Not at all

Perfectly

Kidneys are internally divided into…

cortex: vascular outer portion
medulla: inner portion that is organized into lobes that have renal pyramids
pelvis: innermost portion that collects urine

How well did you know this?

Not at all

Perfectly

The medulla of the kidneys drain into...

minor calyces

The pelvis of the kidneys empty into the...

ureter

Kidneys receive how many percent of cardiac output at rest?

25%, which is the highest basal flow of any tissue under basal conditions

What is the order of blood flow to the kidneys?

1. renal artery, which branches many times 2. interlobular arteries 3. arcuate arteries 4. afferent arterioles 5. glomerulus 6. efferent arterioles (peritubular capillaries and vasa recta) 7. arcuate veins 8. small veins 9. renal veins

What supplies blood to the glomerulus?

afferent arterioles

What is the glomerulus and what is its function?

- ball of fenestrated capillaries | - forms urine

Glomerulus is drained by...

efferent arterioles, which are smaller than afferent arterioles - maintains high hydrostatic pressure in glomerulus, which facilitates filtration

Glomerulus supplies blood to ____, which in turn supplies blood to...

- peritubular capillaries in the renal cortex | - proximal and distal convoluted tubule of nephron, as well as vasa recta

Function of peritubular capillaries in the renal cortex:

- deliver substances to nephron for secretion - return reabsorbed water and solute to blood - supply blood to vasa recta

Where are the vasa recta located?

renal medulla | - accompanies loop of Henle in nephron

Peritubular capillaries drain to...

arcuate veins -> renal veins

Lymphatic vessels are present in _____ but not in _____

- cortex | - medulla

How is the kidney innervated?

- via SNS | - no PNS

SNS innervation effect on the kidney:

- vasoconstricts afferent arterioles to regulate glomerular filtration - stimulates release of renin from granular cells

What is the functional unit of the kidney called?

nephron, which creates urine

T/F: nephron can be regenerated

F, only get what you get at birth and number decreases with age

Nephron undergoes three processes to make urine. What are they?

- glomerular filtration - reabsorption - secretion

What happens during glomerular filtration?

- fluid and dissolved solutes from glomerulus flow into Bowman's capsule - only selective of size - occurs a lot

What happens during reabsorption in the nephron?

- nutrients, ions, and fluids go from nephron into plasma - occurs everywhere in the nephron distal to Bowman's capsule - occurs a lot

What happens during secretion in the nephron?

- wastes move from plasma into nephron - occurs everywhere in the nephron distal to Bowman's capsule - no big impact on body except for K+ and H+

Reabsorption and secretion of the nephron are _____ selective

highly - glucose and amino acids: completely absorbed - inulin: not absorbed at all - H+ and HCO3-: variably absorbed/secreted

Basic structure of the nephron:

- renal corpuscle | - renal tubule

What makes up the renal corpuscle of the nephron?

- Bowman's capsule | - glomerulus

Glomerulus is supplied by _____ and it drains into ____

- afferent arterioles | - efferent arterioles

Structure of glomerulus:

- fenestrated endothelium | - basement membrane

There is a high ____ in the glomerulus, which results in...

- hydrostatic pressure | - ultrafiltrate (protein free fluid) moving from plasma into Bowman's capsule

Structure of Bowman's capsule:

- surrounds glomerulus - filtration membrane made of capillary wall of glomerulus, fused basement membrane, and podocytes - dumps into the renal tubule

Podocytes in Bowman's capsule create...

slit like connections between cells, which are freely permeable to water and small solutes

What excludes large proteins from passing the filtration membrane of the Bowman's capsule?

- size of pores | - negative charges

What can indicate kidney disease?

proteins in urine

What makes up the renal tubule?

- proximal convoluted tubule (PCT) - loop of Henle - distal convoluted tubule (DCT)

Structure of PCT:

- in cortex with peritubular capillaries - cuboidal cells with dense brush border on apical surface - highly invaginated basolateral membrane w/ lots of mitochondria

PCT receives fluid from...

Bowman's capsule

PCT is the major site of...

reabsorption and some secretion

Structure of loop of Henle:

- thin descending loop: dips into medulla - thin ascending loop: both ascending goes back to cortex - thick ascending loop - vasa recta in opposite direction

Function and structure of thin descending loop:

- water gets reabsorbed and returned to ascending vasa recta | - squamous epithelium with few mitochondria

What happens in the thin ascending loop?

Na+ gets passively absorbed and returned to vasa recta

What happens in the thick ascending loop and what is the structure?

- Na+ gets actively absorbed and returned to descending vasa recta - impermeable to water - at junction of afferent arteriole: efferent arteriole and glomerulus form juxtaglomerular apparatus

Structure and function of DCT:

- cuboidal epithelium - no brush border - few invaginations - in cortex with peritubular capillaries - electrolyte balance

Two or more DCT join to form...

cortical collecting tubule, which is where DCT drains into

T/F: collecting tubule and duct system are part of the nephron

F, it is not

Collecting tubule passes through the _____ and collects _____

- medulla (water permeability dependent on [ADH]) | - collects urine

Collecting tubule dumps into the...

renal calyces -> renal pelvis -> ureter