Part One: Excretory System

Does not include all learning objectives (loop of henle stuff not on here)

osmolarity

total solute concentration of a solution expressed as a milliosmoles of solute per litre

osmoregulation

is based on controlled movements of solutes between the body's internal fluids and external environment. Helps keep ur body fluid from being too diluted r too concentrated 

osmosis

occurs when two solutions separated by a permeable membrane differ in osmolarity

units of osmolarity

300 mOSm/L

know what the osmolarity of human blood is

300 mOSm/L

define iso-osmotic, hypo-osmotic, and hyper-osmotic

Iso-osmotic: if two solutions are iso-osmotic, the movement of water is equal in both directions (net movement of water is zero!)

Hyper-osmotic: higher solute concentration, lower free water concentration 

Hypo-osmotic: Lower solute concentration, higher free water concentration. 

if two solutions differ in osmolarity then?

NET flow of water is from the hypoosmotic solution to the hyper osmotic solution 

know the parts of the human kidney , as well as other structure attached to this organ

Renal Cortex + Renal Medulla: kidney is divided into these two regions. 

Renal Calyx: minor calyx collects urine from one renal medulla while each major calyx collects urine from minor calyces. 

Renal Pelvis: collects urine from all the major calyces

Renal artery: supplies kidney blood

Renal vein: drains blood

Ureter: where urine is expelled

List other organs (besides kidney) that are involved in excretion

Skin: water + electrolytes lost thru sweat glands

Lungs: removes co2

Large Intestine: removes solid waste and some water in form of feces

Liver: breaks down toxic substances in blood

. Know the flow of urine starting from collecting ducts all the way to the urethra. 

Collecting Ducts

Minor Calyces

Major Calyces

Renal Pelvis

Ureter

Urinary Bladder

Urethra

filtration

involves transfer of soluble components like water and waste from blood (glomerulus) across bowman's capsule and into nephron. 

reabsorption

involves absorption of molecules ion and water that are necessary for the body to main homeostasis from inside the nephron back into blood.

secretion

involves transfer of molecules (like hydrogen ions, drugs, urea) from blood into nephrons.

Bowman’s capsule

 surrounds and receives filtrate from the glomerular capillaries

nephron

functional unit of kidney: about 1 million of these in each adult kidney!

-Consists of a long single tubules and a ball of capillaries called the glomerulus

Explain how the structure of the glomerulus allows for efficient filtration

Glomerulus has capillaries which have fenestrated endothelium (pores), + podocytes (membranes can fold into slits and ridges) which are permeable to small molecules which can then be filtered out. 

It’s a tangled ball of capillaries (instead of one straight vessel)

→ This creates a large surface area

→ More space = more filtering can happen at once

Identify parts of the human nephron 

Explain difference between afferent and efferent arteriole

Afferent Arteriole: supplies nephron with blood (a branch of the renal artery that divides into the capillaries of the glomerulus)

Efferent Arteriole: Blood leaves the glomerulus (subdivides forms peritubular capillaries)

peritubular capillaries

Peritubular capillaries surround the proximal and distal convoluted tubules

vasa recta

capillaries that extend downward which serve the loop of henle.

Understand when humans release antidiuretic hormone (ADH) + what the target site of this hormone is in the nephron, and the end result following binding of this hormone at the target site

when blood osmolarity rises above 300 more adh is released 

adh is produced in the brain, and released into blood circulation b4 arriving at collecting ducts of the kidney

ADH: increases water RA in collecting ducts of kidney

-retains water and helps body keep hydrated