Homeostasis (10)

Question 1

Epidermis

Answer 1

divided into strata.

Come Let’s Get Sun Burned

• Stratum corneum (top layer)
• stratum lucidum
• stratum ganulosum
• Stratum spinosum
• stratum basale

Question 2

Stratum basale

Answer 2

stem cells and responsible for keratinocytes, that produce keratin.

Question 3

Stratum spinosum

Answer 3

cells become connected to each other; also the site of Langerhans cells.

Question 4

stratum granulosum

Answer 4

keratinocytes die and lose their nuclei.

Question 5

Stratum lucidum

Answer 5

only present in thick, hairless skin, such as on sole of the foot or the plams.

Question 6

Stratum corneum

Answer 6

contains dozen of layers of flattened keratinocytes, forming a barrier.

Question 7

Melanocytes

Answer 7

the cell produces melanin, the pigment that serves to protect the skin from DNA damage caused by UV.

Question 8

Langerhan cells

Answer 8

macrophages that reside with the stratum spinosum. capable of presenting antigens to T-cells in order to activate the immune system.

Question 9

Dermis

Answer 9

Papillary layer- consists of loose connective tissue

Reticular layer- sweat glands, blood vessels, and hair follicles.

Sensory cells:

• Merkel cells (discs)
• Meisssner’s corpuscles
• Rufiini endings
• Pacinian corpuscles

Question 10

Merkel cells ( discs)

Answer 10

responsible for deep pressure and texture sensation within the skin.

Question 11

Meissner’s corpuscles

Answer 11

respond to light touch

Question 12

Ruffini endings

Answer 12

respond to stretch

Question 13

Pacinian corpuscles

Answer 13

respond to deep pressure and vibration.

Question 14

Arrector pilli

Answer 14

In cold conditions, muscle contracts, causing hair of the skin to stand up on the end.

Question 15

Excretory System

Answer 15

regulation of blood pressure, blood osmolarity, acid-base balance, and removal of nitrogenous wastes.

Question 16

Afferent arterioles

Answer 16

blood from the renal artery flows into afferent arterioles which form glomeruli in Bowman’s capsule (first capillary bed)

Question 17

Efferent arterioles

Answer 17

blood then flows through efferent arteriole to the vasa recta (secondary capillary bed) which surrounds the nephron, before leaving the kidney through the renal vein.

Question 18

Movement of fluid in Bowman’s Capsule governed by Starling forces

Answer 18

Hydrostatic pressure in the glomerulus is significantly higher than that in Bowman’s space, which causes fluid to move into the nephron.

The osmolarity of blood is higher than that of Bowman’s space resulting in pressure opposing the movement of fluid into the nephron.

Hydrostatic pressure is larger than oncotic pressure, so the net flow is still from the blood into the nephron.

Question 19

Bowman’s capsule

Answer 19

the fluid will flow from the glomerulus into Bowman’s capsule.

Question 20

Nephron function

Answer 20

keep what the body needs and lose what it doesn’t and concentrate the urine to conserve water.

Question 21

Major waste product excreted in the urine

Answer 21

Mnemonic: Dump the HUNK

• H+
• Urea
• NH3
• K+

Question 22

Proximal convoluted tubule

Answer 22

amino acids, glucose, water-soluble vitamins, and the majority of salts are reabsorbed along with water.

The hydrogen ion, potassium ion, and urea is dumped into PCT

Question 23

descending limb of the loop of Henle

Answer 23

dives deep into the inner medulla of the kidney.
Permeable only to water.

Osmolarity is higher outside of the medulla, so the water will leave from the descending limb of the loop of the Henle. Increasing osmolarity as going down of descending limb of the loop of henle.

Question 24

ascending limb of the loop of Henle

Answer 24

It is water-proof. Only permeable for salts and not permeable to water.

The osmolarity is higher inside the ascending limb of the loop of Henle. The salt will reabsorb, so the osmolarity inside the ascending limb of the loop of Henle will decrease.

Question 25

Distal convoluted Tubule

Answer 25

DCT will respond to Aldosterone and promote sodium reabsorption. Water will follow the sodium, concentrating the urine, and decreasing its volume.

DCT is also a waste production site just like PCT. H+, urea, and K+ will enter.

Question 26

Aldosterone

Answer 26

Steroid hormone regulated by the renin-angiotensin-aldosterone system. Increases sodium reabsorption in the DCT and collecting tube and increasing water reabsorption.

Results in increased blood volume BUT NO CHANGE in blood osmolarity.

Question 27

Collecting Duct

Answer 27

Responsive to both aldosterone and ADH and has high variable permeability, which allows reabsorption of the right amount of water depending on the body’s need.

Question 28

Antiduretic Hormone (ADH) or Vasopressin

Answer 28

Released when low blood volume and also during high blood osmolarity. It increases the permeability of the collecting duct to release water, increasing water reabsorption.

Results in high blood volume AND low blood osmolarity.

Question 29

Countercurrent Exchange

Answer 29

Vasa recta and nephron create a countercurrent multiplier system. The flow of filtrate through the loop of Henle is in the opposite direction from the flow of blood through the vasa recta.

Question 30

Blood pressure

Answer 30

Aldosterone responds to low BP. Low BP stimulates renin from juxtaglomerular cells in the kidney.
Renin cleaves Anginotensiogen to Angiotensin I. Angiotensin I is converted to Angiotensin II by
Angiotensin-converting enzyme (ACE).
Angiotensin II stimulates Aldosterone from the Adrenal cortex.

Aldosterone works by altering the ability of DCT and collecting duct to reabsorb sodium.

Question 31

Bicarbonate Buffer system in kidney

Answer 31

The kidney is able to selectively increase or decrease the secretion of hydrogen ions and bicarbonate. When blood pH is too low, the kidney excretes more H+ and increases reabsorption of bicarbonate, increasing pH. Vise versa

Question 32

pH is too low

Answer 32

respiratory rate is increased blow off more CO2 and favors the conversion of H+ and HCO3- to water and CO2, increasing the pH.