Bio Class 9 Flashcards
Excretory Organs
Colon
- digests solid waste
Liver
- digests hydrophobic waste (waste not absorbed or dissolved in blood)
Kidney
- digests hydrophilic waste
- deals with urine production & excretion
- BP regulation, fluid osmotic balance, pH regulation, activation of vitamin D, stimulating RBC through producing erythropoiten, filtration
Urinary Organs
Adrenal gland (found on top of kidneys) Kidney (2) Ureter Bladder Urethra
Internal vs Extern urinary sphincter
Internal
- involuntary
- smooth muscles
External
- voluntary
- skeletal muscle (striated)
Functional Unit of kidney
nephron
- has millions of nephrons
If reabsorbing water, is a shallow or deep nephron better?
Deep because it will increase in osmolarity the deeper you go into medulla
Renal pelvis
Urine is dumped
Ureter
Connects the kidney to bladder
Reabsorption vs secretion
Reabsorption
- nephron into blood
Secretion
- blood into nephron
Filtration
moving substance across membrane using pressure
Reabsorption
Moving substance from filtrate to blood
- glucose, water, amino acids are reabsorbed
- Na+, HCO3- are reabsorbed *
- K+, H+ are reabsorbed*
- depends on body’s need
Secretion
Moving substance from blood to filtrate
- drugs, toxins, creatine
- Na+, HCO3- are secreted *
- K+, H+ are secreted*
- depends on body’s need
If the body is acidic, what will it secrete? What will it absorb?
It will secrete H+ and absorb HCO3-
Creatine
Waste product from muscle metabolism
- creatine formation and secretion is constant so you can use it to measure function of kidney
What happens in the nephron?
- Blood coming into glomerulus via afferent arteriole and exits via efferent arteriole
- The blood plasma is filtered out and enters the capsule because of the pressure and is not called the filtrate
- Enters proximal convulted tubule which is the main reabsorption and secretion site, relatively unregulated
- Then enters descending loop of henle which is where water reabsorption occurs and it is impermeable to Na+; therefore osmolarity increases
- Then enters ascending loop of henle which is where Na+ reabsorption occurs and is impermeable to water so osmolarity decreases
- Then enters distal convulted tubule which is specialized reabsorption and secretion
- 2 main hormones but mostly aldosterone (which increases Na+ reabsorption and k+ secretion) - Then exits through collecting duct where ADH/vasopressin reabsorbs water
Relationship between:
urine & blood
volume and concentration
If urine volume increases, blood volume decreases BUT urine concentration decreases and blood concentration increases