organ systems

Question 1

how does the body cool itself

Answer 1

trigger in the hypothalamus sends warm blood to skin vessels/capillaries which readily lose heat through sweat and evaporation, ultimately cooling body

Question 2

positive feedback system involving oxytocin and childbirth

Answer 2

growth of the babies head causes increasing pressure on the mother’s cervix, which receptors detect and transmit to the brain. In turn, the brain releases more oxytocin which routes back to the uterus and causes it to contract, inducing more pressure against the cervix and childbirth at a certain point

Question 3

hypertonic, isotonic, hypotonic area

Answer 3

water flows out of cell into surrounding fluid, no change, water flows into cell. tonicity correlates with solute concentration.

Question 4

loop of henle, ADH, gradients, absorption, and urine concentration

Answer 4

in the loop of henle, urine loses water, then loses NaCl, then loops back once again and through the concentration gradient ultimately diffuses water out with the help of ADH. this first occurs past the cortex and urine being passed to the medulla.

ADH also affects collecting ducts. ADH is released when dehydrated.

Through the process, first water is diffused out on the down part of the loop of henle, then solute (NaCl) is diffused on the up part, then on the final downward part water is finally diffused out.

Question 5

kidney structure

Answer 5

blood flows into kidneys directly from the aorta (from the heart) via the renal artery.

the filtered blood returns to the inferior vena cava in the heart through the renal vein.

ureters, tubes from each kidney deposit urine into bladder, where its stored for bodily elimination

Question 6

kidney functions

Answer 6

• removes nitrogenous bases (mammal urea) generated from deamination
• osmoregulation, consequently blood pressure
• regulates blood pH by secreting protons into the nephrons HCO3- (increase and decrease pH, respectively)

Question 7

3 stages of capillary-nephron interaction

Answer 7

1. filtration - high glomerulus pressure pushes a portion of fluids from the blood plasma into the bowmans capsule, whereby capillary blood is transferred to nephrons.
2. reabsorption - refines primary urine by reabsorbing the filtered fluid in the filtration stage, which is essential to keep the body hydrated and retain useful molecules, e.g. salt and glucose. reabsorption often occurs in the proximal tubule. active transport pumps sodium ions out of endothelial cells, creating a gradient. passive transport moves water, glucose, anions, and amino acids following the sodium gradient caused by active transport.
3. Secretion - blood to nephron, protons or bicarbonate or secreted into nephron from blood to regulate pH for transport to the bladder

Question 8

specialized structures on the endothelium of glomerulus that help with the filtration stage:

Answer 8

• fenestrations (pores) - let fluids pass out but restrict erythrocytes, as to prevent them from leaving capillaries and into nephrons
• basement membrane (glycoprotein) filters more tiny molcules to prevent proteins from entering the Bowman’s capsule
• podocytes support the capillaries, prevenitng rupture and final filtration step

Question 9

Urine formation

Answer 9

concentrated urine passed down the collecting ducts where they often come together at the renal pelvis, then the urine is transported down the ureter into the bladder for storage.