A&P II EXAM OBJECTIVE REVIEW

functions of kidneys

filters blood (removes wastes, excess ions, and water), maintains fluid and electrolyte balance, regulates blood pressure pH

kidneys

contain 2-3 million glomeruli per kidney

glomeruli

filter blood based on particule size (exclude blood cells, platelets, proteins)

nephrons

tubules that process filtrate into final urine

typical volume of filtrate produced daily and the amount of urine excreted

150-180 L of filtrate produced daily — <1-2 L urine excrete

filtration in the glomerulus driven by hydrostatic pressure

pushes water/solutes out of glomerular capillaries

filtration in the glomerulus driven by osmotic pressure

opposes filtration; proteins in the capillaries water back

filtration

omvement of plasma into Bowman’s capsule

reabsorption

recovery of water, ions, nutrients

secretion

removal of additional wastes into filtrate

proximal convoluted tubule (PCT)

reabsorbs most water, ions, and nutrients. simple cuboidal cells with brush border — high surface area for reabsorption / reabsorbs most water, ions, and nutrients

loop of Henle

creates concentration of gradient; reabsorbs water and salts. descending thin: simple squamous —> water permeable / ascending thin/thick: simple squamous/cuboidal —> solute absorption

distal convoluted tubule (DCT)

further adjusts filtrate; hormone-regulated

collecting ducts

final adjustment of urine; transport to renal papilla

countercurrent system’s role in water and solute reabsorption

keeps medulla salty which helps recover water efficiently

urine characteristics

color, odor, volume vary with hydration, exercise, diet

• yellow pigment = urochrome (heme breakdown)

• dark urine = dehydration or liver/bile issues

protein in urine

glomerular damage

ketones in urine

fat metabolism; diabetes or low-carb diet

leukocytes/nitrates in urine

possible UTI

blood in urine

abnormal unless menstrual contamination

function of bladder

bladder collects urine from bother ureters; volume = 0-500/600 mL

transitional epithelium role in bladder

adapts to volume changes

detrusor muscle role ni the bladder

contracts to expel urine; weaker with age

micturition reflex

stretch receptors signal spinal cord at ~150 mL —? urge to void

internal sphincters

involuntary smooth muscle

external sphincter

voluntary skeletal muscle —> continence control

parasympathetic activity

detrusor contraction

sympathetic activity

detrusor relaxation during filling

ureter

30 cm long, retroperitoneal tubes connecting kidneys to bladder; lined with transitional epithelium and goblet cells

urethra

transports urine from bladder to outside body; begins at trigone (triangular base of bladder); lined with transitional —> pseudostratified squamous epithelium

female urethra

~4 cm (shorter); leading to higher UTI risk, controlled by the pudenal nerve

male urethra

~20 cm (longer); passes through the prostate, has regions for semen transport and has mucous glands to protect against urine acidity

renal cortex

outer region of the kidney, contains renal corpuscles, proximal and distal tubules

renal medulla

inner region; constraints renal pyramids and papillae

renal pyramids

triangular structures in medulla; contain collecting ducts

renal papillae

tips of pyramids; empty urine into minor calyces

renal hilum

entry/exit point for renal artery, vein, ureter, lymphatics, nerves

renal pelvis

funnel-shaped structure collecting urine from calyces

major calyx

large chamber that collects urine from minor calyces

minor calyx

small chamber receiving urine from papillae

cortical nephrons

short loop, mostly in cortex

juxtamedullary nephrons

long loop, extends deep into medulla

ADH in regulating urine, volume, electrolyte balance, and blood pressure

increases water reabsorption in collecting ducts via aquaporin channels. maintain blood pressure and plasma osmolarity

aldosterone in regulating urine, volume, electrolyte balance, and blood pressure

promotes Na+ reabsorption in DCT and collecting ducts —> water follows —> increases blood volume and pressure. Also promotes K+ excretion

ANH (atrial natriuretic hormone) in regulating urine, volume, electrolyte balance, and blood pressure

released from atria during high blood volume. inhibits Na+ and water reabsorption —> decreases blood volume and pressure

PTH in regulating urine, volume, electrolyte balance, and blood pressure

stimulates conversion of vitamin D —> calcitriol —> increases Ca2+ absorption in gut; blocks phosphate reabsorption —> phosphate excreted —> prevents calcium phosphate buildup. maintains healthy blood calcium levels

buffers contributing to pH regulation

bicarbonate (HCO2-), phosphate, proteins absorb release H+

erythropoietin production and its role in stimulating RBC

kidneys produce 85% of EPO —> stimulates bone marrow. responds to low oxygen (high altitude, exercise, blood loss); kidney failure = anemia = decreased oxygen delivery = fatigue, possible danger

caffeine affecting urine output and blood pressure

vasodilation —> increased GFR

alcohol affecting urine output and blood pressure

inhibits ADH —> decreased water reabsorption

thiazides affecting urine output and blood pressure

blocks Na+/Cl- symporter —> water follows Na+ —> decreased blood volume

osmotic diuretics affecting urine output and blood pressure

mannitol or excess glucose in diabetes —> draw water into urine by osmosis

K+ imbalance

affects nerves, skeletal and cardiac muscle —> arrhythmias, heart failure

importance of water in the body

primary building block of the human body, making up about 60% of an adults total body weight

ICF (inside cells) composition

high in K+, phosphate, magnesium, proteins

ECF (outside cells) composition

high in Na+, Cl-, bicarbonate

importance of protein channels in the movement of solutes

they allow specific solutes — usually ions or small polar molecules — to move across the lipid bilayer that would otherwise block them

edema

swelling caused by excess fluid trapped in body tissues, commonly affecting legs, feet, and hands

edema symptoms

stretched/shiny skin, dimpling after pressure (pitting), and increased size of limbs

how water levels in the body influence the thirst cycle

driven by brain, kidneys, and blood. when water levels drop by even 1-2%, your body triggers a survival mechanism to restore hydration

• controlled by the hypothalamus

• osmoreceptors detect increased solute concentration which triggers thirst sensation, release of ADH and “dry mouth”

main route water leaves the body

Urine — daily loss ~2500 mL

role of ADH and effect on body water levels

kidneys reabsorb water

dehydration and causes of it

when body loses more fluids (water and electrolytes) than it takes in — diarrhea and vomiting, fever, excessive sweating, and incresed urination

sodium (Na+)

major extracellular action, controls osmotic pressure and fluid balance — regulated by kidneys

potassium (K+)

major intracellular action, maintains resting membrane potential, essential for nerve and muscle function

Chloride (Cl-)

major extracellular anion, maintains electrical neutrality and hydration

bicarbonate (HCO3-)

maintains acid-base balance (buffer system)

Calcium (Ca2+)

stores in bones and teeth, needed for muscle contraction, blood clotting, and neurotransmitter release; regulated by Vitamin D

Phosphate (PO42-)

important for ATP (energy), DNA/RNA structure and cell membranes

hypernatremia

high sodium — swelling of cells; brain damage risk

hyponatremia

low sodium — dehydration, increased blood concentration

hyperkalemia

high potassium — weakness, reduced nerve activity

hypokalemia

low potassium — dangerous = heart might stop

hyerpcalcemia

high chloride

hypochloremia

low chloride

hyperphosphatemia

high phosphate

hypophosphatemia

low phosphate

predominant extracellular anion

chloride (Cl-)

aldosterone role on the level of water in the body

increased Na+ reabsorption = increased K+ excretion; increased water retention = increased blood volume

most powerful buffer system in the body

protein buffers, phosphate buffers, and mostly bicarbonate-carbonic acid buffer

increased CO2 affecting blood pH

decreased pH (acidic) = hypoventilation

decreased CO2 affecting blood pH

increased pH (alkaline) = hyperventilation

3 blood variables considered when making diagnosis of acidosis or alkalosis

blood pH, pCO2 (respiratory component) and HCO3 (metabolic component)

scrotum

skin-covered muscular sac that holes the testes and acts as a climate control system

penis

delivers sperm into the female reproductive tract

testes

produce testosterone and generate sperm

seminiferous tubules

site of spermatogenesis

head of sperm cell

contain haploid nucleus and acrosome (enzymes for fertilization)

midpiece of sperm cell

contains mitochondria for energy (ATP)

tail of sperm cell

also known as the flagellum, provides motility

spermatogenesis

production of sperm cells

events during spermatogenesis that produce haploid sperm from diploid cells

spermatogonia (diploid stem cells), primary spermatocytes, secondary spermatocytes, spermatids, spermatozoa (mature sperm)

importance of testosterone in male reproductive function

driving the development of sex organs, enabling spermatogenesis, and regulating libido

ovaries

produces oocytes and hormones (estrogen and progesterone)

uterine tubes

transport the egg, fertilization usually happens here

uterus

houses and nourishes a developing fetus until birth

vagina

passageway for menstrual flow, receives sperm during intercourse, birth canal during delivery

mons pubis

fatty tissue over pubic bone

labia majora

outer folds of skin

labia minora

inner folds protecting openings