Anatomy 2 renal system

what are the 6 major kidney functions

• Excrete metabolic waste

• balance electrolytes and water

• maintain nutrients durung starvation

• regulate blood pressure

• secrete hormones

which metablic wastes are listed in the sides

cratinine, uric acid, urea, and amminium ion

what is creatinine

a waste product associated with muscle breakdown and protein digestion

where does uric acid come from

purine breakdown

what is urea produced from

nirtrogen compunds firmed during metabolism also connected to amino acid oxidation

what role do ammonium ions play

they help maintain acid base balance

which electrolytes/ ions do the kidneys help regulate

Na+, K+, Cl-, HCO3- (bicarbonate), and HPO42- (phosphate)

how do kidneys helo maintain water balance

by adjusting water and sodium handling and producing diluted or concentrated urine

what is gluconeogenesis in the renal system

maintaining blood nutrients during starvation using sources such as amino acids and fatty acids

how do kidneys help regulate blood pressure

they control ectracellulat fluid volume by changing urine concentration and volume

which hormones or hormone- reguated substances are listed with renal regulation

Aldosterone, renin, angiotensin 1 and 2, ADH, and ANH

where are the kidneys located

in the abdominal cavity, on the posterior abdominal wall:they are retroperitoneal

between which vertebral levels are the kidneys located

approximately T11 to L2

what is the general shape and size of the kidney

bean shaped and about the size of a clenched fist

whitch kidney sits more superiorly

the left kidney

what protects the kidney

a layer of connective tissue and fat

what is the renal hilum

the medial indentation where the renal artery and nerves enter and the ureter exits

what is the renal pelvis

the structure that collects urine and transports it t the ureter

what are the two main kidney layers

the cortex (outer)

medulla (inner)

what structures are found in the renal cortex

renal columns and cortrcal nephrons, renal corpuscles and convoluted tubules

what are renal columns

extensions of the cortex between the pyramids that project into the medulla

what structures are found in the renal medulla

renal pyramids, collecting ducts, renal papillae, and minor and major calyces

what is the corticomedullary junction

the boundary where the widened end of a renal pyramid meets the cortex

what is a renal pyramid

a conical subdivision of the medulla that reveives urine from the cortex

what is the renal papilla

the apex of a renal pyramid

what is a minor calyx

a funnel shaped cup located distal to a renal papilla

what is a major calyx

a larger calyx formed by the joining of manir calyces

what do collecting ducts do

receive fluid from nephrons and transport it toward the renal papilla/ urinary outflow

what is the collecting ducts relationship to nephron types

it receives urine fron both cortical and juxtamedullart nephrons ad marks a cisual distinction between them

what are the ureters

small tubes that connect each kidney to the urinary bladder

where do the ureters originate and exit the kidney

they form from the renal pelvis and exit at the hilum

how is urine mived through the ureters

peristalsis: stretching activates a reflex that contracts the ureters muscle

what are the 3 layers of the ureter wall

Mucosa (inner)

smooth muscle (middle)

fibrous connective tissue (outer)

where is the urinary bladder licated, and what does it do

in the pelvic cavity: it stiores urine

what is the baldder trigone

a triangular area at the bladder base outlined by the two ureter openings and the urethral opening

what bladder strorage capacity is given in the slides

about 300-350 mL

what is the detrusor muscle

the thick smooth-muscle layer of the bladder wall, arranged in several directions

what allows the bladder lining to stretch

trabsitional epithelium and rugae (folds) in the mucosa

what are the four bladder wall layers

adventitia, muscularis, submucosa, inner mucosa

what is the urethra

an epithelial- lined fibromuscular tube that carries urine from the bladder outside the body

what are the two urethral sphincters

the internal sphincter and external sphincter

what type of muscle makes up the external urethral sphincter

skeletal muscle: it is under voluntary control

how long are the urethras

male: 8in

females: 1.5-2 in

how does the male urethra differ from the female urethra

the male urinary and reproductive system share the urethra: the female systems are separate

what are the 3 regions of the male urethra

prostatic, membranous, and penile

why can bacteria enter the female bladder more easily

the female urethra is shorter and close to the rectum

what triggers the micturition reflex

stretching of the bladder wall as it fills

what type of reflex is micturition

an antonomic reflex that can be voluntarily inhibited

what happens when baldder stretch receptors are activated

signals travel through sacral parasymathetci nerves to the spinal cord, causing baldder contraction

what happenss during mucturition facilitation

the detrusor contracts, sphincters relax, and urine flows out

what happends during michturition inhibitions

nerve impulses keep the sphincters contracted, preventing urine flow

at about what bladder volume are stretch receptors stimulated

250 mL

what can bladder infections do to sensory nerve signaling

increase action potentials, creating a feeling of fullness even when the bladder is empty

what are the 2 main nephron types

cortical nephrons and juxtamedullary nephrons

what percentage of nephrons are cortical

85%

where are cortical nephron renal corpuscles located

in the outer cortex

how deep do cortical nephrons loops of henle extend

they do not penetrate deeply into the medulla

what perventage of nephrons are juxtamedullary

15%

where are juxtamedullary renal corpuscels located

near the corticomedullary junction

what is the key fucnction of juxtamedullary nephrons

they generate the medullary osmotic gradient that supports water reabsorption and concentrated urine

how many nephrons are in each kidney

about 1.3 million

what is the nephrons overall job

filter blood plasma to make urine and help regulate pH by secreting H+

what structures make up a nephron

renal corpuscle, PCT, loop of henle,DCT, asnd collecting duct

what makes up the renal corpuscle

the glomerulus and bowmans (glomerular) capsule

what is the glomerulus

a ball/ network of capillaries inside bowmans capsule

what is the afferent arteriole

the larger vessel entering the glomerulus

what is the efferent arteriole

the vessel leaving the glomerulus: its diameter is smaller than the afferent arteriole

what is bowmans capsule

a double-walled chamber surrounding the glomerulus and receiving the first filtrate

where does the first step of urine formation occur

at the renal corpuscle, as plasma is filtered from glomerular capillaries into bowmans capsule

what does the procimal convoluted trubule (PCT) do

it is closest to the renal corpuscle and is the major site of reabsorption of water and useful solutes

what does the loop of henle do

creates a concentration gradient in the medulla that supports sodium and water handling

what are the two limbs of the loop of henle

descending limb and ascending limb, joined by a hairpin turn

what does the distal convoluted tubule (DCT) help regulate

sodium, potassium, and calcium throught secretion and additional reabsorption

what do peritubular capillaries surround

cortical nephrons: they allow most water reabsorption to return to the blood

what is the vasa recta

the capillary bed addociated with juxtamedullary nephrons: it supports concentrated urine

what are granular cells in the DCT region described as doing

they contain renin granules and act as mechanoreceptors, according to the slides

what do macula densa cells detect

changes in water/ ion levels, specially sodium chloride in the filtrate

what is renal blood flow

the amount of blood passing through the kidneys per minute

what percentage of cardiac output flows though the kidneys

21%

how much urne is produced per day

1-2 liters

how often do the kidneys filter the bodys entire plasma volume

about 60 times per day

what is filtrate

fluid filtered from plasma into bowmans caosule: it lacks blood cells and platelets

what are the 3 steps of urine formation

Filtration, reabsorption, and secretion

where does filtration occur

at the renal corpuscle (glomerulus into bowmans capsule)

where does reabsorption occur

along the renal tubules, moving needed substances from filterate back to blood

where does tubular secretion occur

from periubular capillaries into the tubules, especially the late DCT and collecting ducts

what drives filtration

systemic blood pressure creats the presssure gradient that pushes fluid out of glomerular capillaries

what does filtrate normally contain

water, nutrients, and essential ions, but not blood cells or large proteins

what are formed elements, and where do they go during filtration

RBC, WBC, and platelets: they remain in the blood and leave via the efferent arteriole

what is glomerular filtration rate (GFR)

the volume of fluid filtered from glomerular capillaries into bowmans capusuke per unit time

what 3 factors affect GFR

blood flow/ pressure through afferent and efferent arterioles, filtration surface area, and membrane permeability

what happends when filtration pressure increases

filtrate formation and urine volume increases

what happends when filtration pressure decreases

filtrate formation and urine volumer decrease

what can influence filtration pressure

systemic blood pressure, hydration status, health conditions, and plasma protiens

why must GFR stray within a narrow range

to high: needed substances may be lost

to low: wastes may be reabsorbed insteas of removed

what is capsular pressure

the pressure from fluid already in bowmans capsule that opposes filtration: about 15mmHg

what is blood colloid osmotic pressure (BCOP)

the inward pull of water caused by plasma protiens: about 30mmHg

what glomerular pressure value is listed in the slides

about 55mmHg, greater than capsular and colloid pressures

what is creatinine clearance used to estimate

GFR; it measures the plasma volume cleared of creatinine per unit time

how does sympathetic stimulation affect the afferent arteriole

it constricts it, decreasing renal blood flow, filtraion, and urine output