exam 5 bio

osmolarity

amount of solute (ions, molecules, intracellular proteins) per liter of solution (water/blood in or out of cell)

osmoregulation

• control of water & ion balance (regulation of osmolarity)

• impacts cell volume, manages homeostasis functions, BP & BV)

osmosis

• diffusion of water → sample or facilitated diffusion

• relies on aquaporins

• predict direction of passive water movement → water & solute relationship

osmotic pressure

pressure needed to prevent water from moving by osmosis across a selectively permeable membrane

higher solute concentration & lower water concentration

• higher osmotic pressure

• HYPERTONIC → CELL SHRINKS

lower solute concentration & higher water concentration

• lower osmotic pressure

• HYPOTONIC → CELL BURSTS

osmoconformers

• osmolarity matches/conforms to environment

• regulate concentrations of particular ions in their body fluids

osmoregulators (humans!)

• osmolarity is regulated within a range that differs from environment, regulates OWN osmolarity

• use more energy to regulate pressure than osmoconformers

isomatic

• animals keep their intracellular & extracellular fluids at this

  • nature of solutes in these 2 areas can differ

• balance of solutes inside body vs outside body

nitrogenous waste

• from protein & nucleic acid breakdown & digestion

• managed by our kidneys & digestive tracts

ammonia (TOXIC!)

• damages neurons

• disturbs pH

• works for fish → easily released into water through gills

• requires a ton of water (MOST)

• not a lot of energy

urea (mid level toxic)

• can’t be released into air

• concentrated in liver

• sent to kidneys

• use water in urine to get rid of it - 2nd most

uric acid (least toxic)

• takes energy to make

• doesn’t need a lot of water to excrete - LOWEST

filtration

• occurs in GLOMERULUS, initial filtering of solutes from blood to form FILTRATE

• relies on BP (too high/low)

• NON SELECTIVE → stuff just moves from blood into the tube

reabsorption

• PERITUBULAR CAPILLARIES - PCT, DCT, LOOP OF HENLE

• molecules OUT of nephron thru channels/pumps

• keeps certain amounts of H2O, glucose, NaCl

• SELECTIVE - rely on a special transport epithelium

secretion

• fluids/molecules moves back INTO nephron

• thing sbody wants to get rid of (excess bicarbonate, etc)

• SELECTIVE - rely on a special transport epithelium

excretion

urea/CO2/waste released into the environment

nephrons

• type of excretory tubule/functional unit of kidney

• control retention of water/ions & molecules

vertebrate kidneys

• specialized organ containing millions of excretory tubules (nephrons)

• blood exits blood vessels through specialized leaky capillary walls

blood delivery to glomerulus

• afferent arteriole (arrive)

• efferent arteriole (exit)

glomerulus

• FILTRATION occurs here

• network of capillaries that filters blood, water & small molecules

  • capillaries have PORES (endothelial cells, basal lamina, podocytes) → big to let water & nutrients into bowman’s capsule, small enough to prevent blood vessels being lost

  • blood vessels of it move water & solute into bowman’s capsule

bowman’s capsule

• cup shaped structure that surrounds glomerulus & collects filtrate

• water & solutes diffuse thru membrane of capillaries into this

PCT (proximal convoluted tubule)

• REABSORPTION OCCURS!

• reabsorbs most water, ions (electrolytes), & nutrients (glucose & amino acids) back into blood

• Na/K pump moves Na OUT of tubule

• Cl- are drawn w positive ions, OUT

• water moves out of tube/diffuses by osmosis in SAME DIRECTION as electrolytes & solutes (aquaporins)

loop of henle

• lets us have concentrated interstitial fluid in medulla

• makes a concentrated in interstitial fluid

• vasa recta

vasa recta

• blood vessels wrapped around nephrons

  • sucks up fluid & solutes

  • interact w interstitial fluid to not lose a lot of water, no lose or gain of water

descending loop of henle - FIRST

recapture water → passive osmosis

ascending loop of henle - SECOND

• lower part: reabsorb/passive salts diffuse out → no aquaporins

• thick upper part: salts ACTIVELY transported out of tube to interstitial fluid

DCT (distal convoluted tubule)

• SECRETION OCCURS!

  • secretes H+, wastes, K+, etc ACTIVELY INTO nephron

• more water reabsorbed & various ions

• secretion of extra wastes into filtrate

• regulates blood pH (bicarb & protons)

• responsive to aldosterone

collecting duct

urine concentration

ureter

• where concentrated urea-containing fluid from kidneys go

• connect the renal pelvis of the kidney to bladder

bladder

• where ureters transfer urine

• stores urine prior to excretion

interstitial fluid

extracellular fluid, juice of a tissue, most immediate liquid surrounding a cell

flow of filtrate

1. renal artery takes blood (toxins) into kidney

2. kidneys clean blood of toxins, flows out thru renal vein

3. ureter receives concentrated area w fluid

4. bladder receives ureter transfer (urine)

5. urethra has urine flowing before final excretion

kidney osmoregulation

• antidiuretic hormone

  • reduces BV

  • concentrates urine further via aquaporin insertion in collecting duct

RAAS

renin angiotensin aldosterone system

RAAS stimulus

low salt in blood, LOW BV

RAAS sensor

juxtaglomerular apparatus

RAAS process

1. juxtaglomerular apparatus releases renin

2. renin cleaves angiotensinogen

3. angiotensinogen becomes angiotensin 1

4. angiotensin 1 is cleaved by ACE from lungs

5. angiotensin 2 made

RAAS result

• bind angiotensin 2 receptors on SMOOTH MUSCLE

  • vasoconstriction → HIGH BP

• bind angiotensin 2 receptors on ADRENAL CORTEX

  • releases aldosterone → MORE Na reabsorption in nephron