BIO Ch. 10 Homeostasis

Question 1

What are the organs of the excretory system?

Answer 1

kidneys, uterus, bladder and urethra

Question 2

What is the path of urine?

Answer 2

the nephrons empty into the renal pelvis to the uterus down to the bladder and through the urethra to exit out of the body

Question 3

What is the function of the renal hilium?

Answer 3

point of entry and exit for the renal artery, renal vein, and ureter

Question 4

What is the difference b/w the afferent and efferent arteriole pathways in the kidneys?

Answer 4

afferent arterioles carry blood towards the glomeruli in the Bowmen’s capsule. efferent arterioles carry blood away from the glomerulus to the vasa recta which is surrounded by nephrons before leaving through the renal vein

Question 5

What are the waste products secreted in urine?

Answer 5

H+ ions, urea, NH3, K+

Question 6

How is ammonia excreted?

Answer 6

the liver converts ammonia to urea which travels to the nephrons to be excreted with urine

Question 7

How is aldosterone secreted?

Answer 7

aldosterone (a steroid) hormone is secreted by the adrenal cortex in response to decreased BP. When secreted, it stimulates the release of renin from the juxtaglomerular cells in the kidney. renin cleaves angiotensinogen, a liver protein that forms angiotensin I. Angiotensin I is metabolized to angiotensin II in the lungs. angiotensin II promotes the release of aldosterone

Question 8

What is the role of aldosterone in the kidneys?

Answer 8

it increases salt reabsorption in the distal convoluted tubule and collects thereby increasing water reabsorption and blood volume which in turn increases blood pressure. it also increases potassium and hydrogen ion excretion.

Question 9

What is the role of the kidneys?

Answer 9

Regulation of Water and Electrolyte Balance, Excretion of Metabolic Waste, Excretion of hormones and drugs, Regulation of Arterial Blood Pressure, Regulation of Red Blood Cell Production, Regulation of Vitamin D Production, and Metabolism

Question 10

What happens if more sodium is reabsorbed?

Answer 10

if more sodium is reabsorbed, water will follow, the blood volume will increase, and therefore BP increases

Question 11

What is the diff b/w ADH and aldosterone?

Answer 11

ADH governs only water reabsorption and thus lowers blood osmolarity. aldosterone causes both salt and water reabsorption and does not change blood osmolarity

Question 12

What is the role of ADH/vasopressin in the kidneys?

Answer 12

ADH (peptide) hormone is made by the hypothalamus and released by the posterior pituitary in response to high blood osmolarity and low blood volume. it increases water reabsorption in the collecting ducts, which results in an increased blood volume and pressure, and decreases blood osmolarity

Question 13

What happens at the renal cortex?

Answer 13

where filtration and reabsorption occur - proximal and distal convoluted tubule are found here

Question 14

What is oncotic pressure?

Answer 14

osmotic pressure due to dissolved proteins

Question 15

What happens at the glomerulus?

Answer 15

(ball of capillaries), where plasma filtration occurs

Question 16

What happens at the vaso recta?

Answer 16

(second capillaries) reabsorption of vital nutrients

Question 17

What are the 2 sphincter muscles of the bladder?

Answer 17

internal urethral - consists of smooth muscle and is under involuntary PNS control
external urethral - consists of skeletal muscles and is under voluntary control

Question 17

What controls the detrusor muscle?

Answer 17

the detrusor muscles line the bladder and are under parasympathetic control

Question 18

What are the 3 processes of solute movement in the kidneys?

Answer 18

Filtration - the moment of solutes from the blood to filtrate at the Bowmen’s capsule at the rate determined by sterling forces
Secretion - the movement of solutes from the blood to filtrate anywhere other than the bowman’s capsule
Reabsorption - the movement of solutes from the filtrate to blood

Question 19

What is the function of the proximal convoluted tubule segment of the nephron?

Answer 19

bulk reabsorption of glucose, amino acids, soluble vitamins, salts, and water. It is also the site of the secretion of hydrogen and potassium ions, ammonia, and urea

Question 20

What is the function of the Ascending loop of Henle segment of the nephron?

Answer 20

salt reabsorption and allowing dilution of the ruined in the diluting segment in the outer medulla

Question 20

What is the function of the descending loop of Henle segment of the nephron?

Answer 20

water reabsorption using the medullary concentration gradient. the Vasa recta and nephron flow in opposite directions, creating a countercurrent multiplier system that allows maximal reabsorption of water

Question 21

What is the function of the distal convoluted tubule segment of the nephron?

Answer 21

responsive to aldosterone and is the site of salt reabsorption and water. It is also the site of the secretion of hydrogen and potassium ions, ammonia, and urea

Question 22

What is the function of the collecting duct segment of the nephron?

Answer 22

site for urine concentration. responsible to both ADH and aldosterone and has variable permeability, which allows reabsorption of the right amount of water depending on the body’s need

Question 23

What are the 3 layers of the skin?

Answer 23

hypodermis (subcutaneous layer), dermis, and epidermis

Question 24

What are the 5 layers of the epidermis?

Answer 24

1. stratum basale - contains stem cells that proliferate to form keratinocytes
2. stratum spinosum
3. stratum granulosum
4. stratum lucidum - contains dead keratinocytes
5. stratum corneum - formed by many thin layers of keratinocytes

Question 25

What is the role of Langerhans cells?

Answer 25

Langerhans cells are specialized macrophages that serve as antigen-presenting cells in the skin

Question 26

What are the 2 layers of the dermis?

Answer 26

papillary -contains loose connective tissue
reticular - consists of dense connective tissue

Question 27

What cells are contained in the dermis?

Answer 27

Merkle cells - deep pressure and texture senses
free nerve endings for pain sensation
Meissner’s corpuscles - light touch senses
Ruffini endings - stretch
Pacinian corpuscles - deep pressure and vibration

Question 28

What cells are contained in the hypodermis?

Answer 28

fat and connective tissue, and connects the skin to the rest of the body

Question 29

What is the role of the skin?

Answer 29

thermoregulation, and prevents dehydration and salt loss from the body

Question 30

What Is the mechanism for warming?

Answer 30

arrector pili muscles contract, causing hairs to stand on end, trapping a layer of warm air around the skin, vasoconstriction, occurs, the body shivers, and the insulated by fat

Question 31

What is the flow of excretion?

Answer 31

Bowmn’s space –> PCT –> Descending limb of the loop of Henle –> ascending limb of the loop of Henle
–> DCT –> collecting duct –> renal pelvis –> ureter
–> bladder –> urethra

Question 32

What are the vessels in the renal vasculature?

Answer 32

renal artery –> afferent arteriole –> glomerulus –> efferent arteriole –> vasa recta –> renal vein

Question 33

Where can proteins be found in the urine?

Answer 33

only in the glomerulus because other nephron structures cannot reabsorb large proteins if they pass through the glomerulus

Question 34

What is the function of the nephrons?

Answer 34

to make urine that is hypertonic to the blood

Question 35

What substance is excreted in high volumes in the urine when the pH of blood is high?

Answer 35

bicarbonate ions