MCAT Biology Ch. 10 Homeostasis

• Regulation of blood pressure
• Regulation of blood osmolarity
• Regulation of acid-base balance
• Removal of nitrogenous wastes

Produces urine

The widest part of the ureter, which is where urine is dumped into directly from the kidney

The kidney's outermost layer

Sits w/in the cortex of the kidney

Each kidney contains one, & it contains a renal artery, renal vein, & ureter

Kidney contains a portal system, w/ 2 capillary beds in series.

1. Renal artery passes thru medulla & enters cortex as afferent arterioles. The highly convoluted capillary tufts derived from the afferent arterioles are called glomeruli & they are surrounded by Bowman's capsule.
2. After blood passes thru glomerulus, the efferent arterioles then form a second capillary bed. These capillaries surround the loop of Henle & are called vasa recta

Surrounds the glomeruli that are the capillaries derived from the afferent arterioles

Surrounds the nephron (the second capillary bed)

Muscular lining of bladder, under parasympathetic control

• Internal Urethral Sphincter - consists of smooth muscle & is under involuntary (parasympathetic) control; is normally contracted
• External Urethral Sphincter - consists of skeletal muscle & is under voluntary control

When bladder is full, stretch receptors tell nervous system that bladder requires emptying. Causes parasympathetic neurons to fire, & detrusor muscles contracts. This causes internal urethral sphincter to relax; the rest of it is not reflex & is up to individual because the external urethral sphincter is under voluntary control

1. Filtration
2. Secretion
3. Reabsorption

Movement of solutes from blood (glomerular capillary) to filtrate at Bowman's capsule. Direction & rate of filtration is determined by Starling forces, which account for the hydrostatic & oncotic pressure differentials between the glomerulus & Bowman's space (various pathologies can change the normal flow, which is from the glomerulus into Bowman's space)

Movement of solutes from blood to filtrate anywhere other than Bowman's capsule (ex: secretion directly from nephron to tubule thru active or passive transport)