Homeostasis (Excretory system)

Question 1

List the structures in the excretory pathway, from where filtrate enters the nephron to the excretion of urine form the body

Answer 1

Bowmans’s space > proximal convoluted tubule > descending limb of the loop of henle > ascending limb of the loop of henle > distal convoluted tubule > collecting duct > renal pelvis > ureter > bladder > urethra

Question 2

List the vessels in the renal vascular pathway, starting from the renal artery and ending at the renal vein

Answer 2

Renal artery > afferent arteriole > glomerulus > efferent arteriole > vasa reacta > renal vein

Question 3

What arm of the nervous system is responsible for contraction of the detrusor muscle?

Answer 3

The parasympatheic nervous system causes contraction of the detrusor muscle

Question 4

What are the three processes by which solutes are exchanges between the filtrate and the blood? What happens in each?

Answer 4

1. Filtration- it is the movement of solutes from blood into filtrate at Bowman’s capsule
2. Secretion- It is the movement of solutes from blood into filtrate anywhere besides Bowman’s capsule
3. Reabsorption- it is the movement of solutes from filtrate into blood

Question 5

Bowman’s capsule

Answer 5

Site of filtration, through which water, ions, amino acids, vitamins, and glucose pass ( everything except cells and proteins)

Question 6

Proximal convoluted tube

Answer 6

Controls solute identity, reabsorbing vitamins, amino acids and glucose, while secreting potassium and hydrogen ions, ammonia and urea

Question 7

Descending limb of the loop of henle

Answer 7

It is important for water reabsorption using the medullary concentration gradient. Permeable to water, so water reabsorbed

Question 8

Ascending limb of the loop of henle

Answer 8

Permeable to solutes so solutes reabsorbed and not permeable to water. Important for salt reabsorption and allowing dilution of urine in the diluting segment

Question 9

distal convoluted tube

Answer 9

Important for solute identity by reabsorbing salts while secreting potassium and hydrogen ions, ammonia, and urea

Question 10

Collecting duct

Answer 10

It is important for urine concentration; its variability permeability allows water to be reabsorbed based on the needs of the body

Question 11

How does the kidney control the acid-base balance?

Answer 11

When the blood pH is low, the kidneys excrete H+ ions and increase absorption of bicarbonate, resulting in vice versa.

Question 12

What happens when blood osmolarity is low?

Answer 12

Excess water will be excreted, while solutes will be reabsorbed in higher concentrations and vice versa.

Question 13

Distal convoluted tube responds to what hormone?

Answer 13

Aldosterone (steroid hormone)

Question 14

Collecting duct responds to what hormone?

Answer 14

Aldosterone (steroid hormone) and antidiuretic hormone (ADH or Vasopressin- peptide hormone) . It reabsorbs water by increasing the permeability of collecting duct but h20

Question 15

Difference between Aldosterone and antidiuretic hormone?

Answer 15

ADH governs water reabsorption and thus results in a lower blood osmolarity (greater h20 in blood).It reabsorbs na from convoluted tubule and collecting duct. Aldosterone causes both salt and water reabsorption and does not change blood osmolarity

Question 16

What is the predominant cell type in the epidermis?

Answer 16

Keratinocytes are the primary cells of the epidermis

Question 17

What are the layers of epidermis, from superficial to deep?

Answer 17

Stratum corneum, Stratum lucidum, Stratum granulosum, Stratum spinosum, Stratum basal

Question 18

What are the layers of the dermis, from superficial to deep?

Answer 18

The papillary layer and reticular layer

Question 19

What are the cooling mechanism used by the body?

Answer 19

Cooling mechanism include sweating, which absorbs heat from the body through evaporation of water from sweat, and vasodilation. Sweat glands are innervated by postganglionic cholinergic sympathetic neurons

Question 20

What is the warming mechanism used by the body?

Answer 20

Warming mechanism include piloerection, in which arrector pili muscles contract, causing hair to stand on end ( trapping a layer of warmed air around the skin), vasoconstriction, shivering and insulation provided by fat.

Question 21

Where are most sensory cells located? And what are some examples?

Answer 21

In the dermis
- Merkel cells (deep pressure and texture)
- free nerve ending (pain)
- Meissner’s corpuscles (light touch)
- Ruffini endings (stretch )
Pacinian corpuscles (deep pressure and vibration)

Question 22

Hypodermis

Answer 22

Deepest layer of the skin

- Contains fat and connective tissue and connects the skin to the rest of the body

Question 23

Langerhans cells

Answer 23

Special macrophages that serve as antigen-presenting cells in skin
- in stratum spinosum

Question 24

How is Na+ transported?

Answer 24

Na+ is actively transported out of the nephron in the proximal and distal convoluted tube where concentration outside is greater than inside, this energy is need to move Na+ against its gradient. But in the ascending tube, Na+ is moved passively down the gradient.

Question 25

What regulates body temp?

Answer 25

hypothalamus
- When its cold outside, nervous stimulation to the blood vessels in the skin is increased, causing vessels to constrict. This constriction diminishes blood flow to the skin surface and prevents heat loss. Sweat glands are turned off to prevent heat loss through evaporation. Skeletal muscles are stimulated to shiver (rapidly contract), which increases the metabolic rate and produces heat.

Question 26

What layer of skin is mostly loose connective tissue?

Answer 26

Papillary layer of the dermis

Question 27

Which layer of the epidermis contain dead keratinocytes?

Answer 27

Stratum corneum and stratum lucidum

Question 28

What does reticular layer contain in dermis?

Answer 28

Dense connective tissue