Homeostasis

Question 1

Functions of the excretory system

Answer 1

The regulation of blood pressure, blood osmolarity, acid-base balance, and removal of nitrogenous wastes. –> kidney plays essential role

Question 2

Parts of the excretory system

Answer 2

Kidneys, ureters, bladder, and urethra

Question 3

Cortex

Answer 3

The kidney’s outermost layer

Question 4

Medulla

Answer 4

Part of the kidney that sits within cortex

Question 5

Hilum

Answer 5

A deep slit in the center of the liver’s medial surface

Question 6

Renal pelvis

Answer 6

Widest part of the ureter; spans almost the entire width of the renal hilum

Question 7

Describe the kidney’s portal system

Answer 7

Renal artery branches out, passes through the medulla, and enters the cortex as afferent arterioles. Highly convoluted capillary tufts derived from these afferent arterioles are known as glomeruli. After blood passes through a glomerulus, the efferent arterioles then form a second capillary bed. The capillaries surround the loop of Henle and are known as vasa recta.

Question 8

Bowman’s capsule

Answer 8

A cuplike structure located around the glomerulus.

Question 9

What are the parts of the long tubule the Bowman’s capsule leads to

Answer 9

The proximal convoluted tubule, descending and ascending limbs of Loop of Henle, distal convoluted tubule, and collecting duct.

Question 10

Detrusor muscle

Answer 10

Muscular lining of bladder:parasympathetic activity causes the detrusor muscle to contract

Question 11

Internal urethral sphincter

Answer 11

Consists of smooth muscle, and is contracted in its normal state. Made of smooth muscle and is under involuntary control

Question 12

External urethral sphincter

Answer 12

Consists of skeletal muscle and is under voluntary control

Question 13

What happens when the bladder is full/micturition reflex

Answer 13

Stretch receptors convey to the nervous system that the bladder requires emptying –> causes parasympathetic neurons to fire, and the detrusor muscle contracts –> in turn causes internal sphincter to relax.

Question 14

3 broad different kidney process kidney function can be divided into

Answer 14

Filtration, secretion, and reabsorption

Question 15

Filtration

Answer 15

The nephron’s first function: approximately 20 percent of the blood that passes through the glomerulus is filtered as fluid into Bowman’s space.

Question 16

Starling forces in Bowman’s spaces

Answer 16

Governs movement of fluid in Bowman’s space.
Hydrostatic pressure in the glomerulus is significantly higher than that in Bowman’s space, which causes fluid to move into the nephron.
Osmolarity of blood is higher than that of Bowman’s space, resulting in pressure opposing the movement of fluid into the nephron.
NET: hydrostatic pressure much larger than oncotic pressure, so net flow is still from blood into nephron

Question 17

What do nephrons secrete

Answer 17

They secrete salts, acids, bases, and urea directly into the tubule by either active or passive transport.

Question 18

How is nitrogen secreted

Answer 18

Ammonia (NH3) is a byproduct of the metabolism of nitrogen-containing compounds and, as a base, can disturb the pH of blood and cells.
liver converts ammonia to urea, a neutral compound, which travels to the kidney and is secreted into the nephron for excretion in the urine.

Question 19

Reabsorption

Answer 19

When some compounds that are filtered or secreted may be taken back up for use. Certain substances are almost always reabsorbed, such as glucose, amino acids, and vitamins

Question 20

summary of filtration, secretion, and reabsorption

Answer 20

Filtration: movement of solutes from blood to filtrate at Bowman’s capsule
Secretion: movement of solutes from blood to filtrate anywhere besides Bowman’s capsule
Reabsorption: movement of solutes from filtrate to blood

Question 21

Proximal convoluted tubule (PCT)

Answer 21

First place after bowman’s capsule the filtrate enters. Amino acids, glucose, water-soluble vitamins, and the majority of salts are reabsorbed along with water. About 70% of filtrate reabsorbed here, but the filtrate remains isotonic to the interstitium, as other solutes and a large volume of water are also absorbed.
PCT is also the site of secretion for a number of waste products, including H+ ions, potassium ions, ammonia, and urea.

Question 22

What happens to solutes reabsorbed into the interstitium in the nephron

Answer 22

They are picked up by the vasa recta to be returned to the bloodstream for reuse within the body.

Question 23

Major waste products excreted in the urine

Answer 23

Dump the HUNK: H+, Urea, NH3, and K+

Question 24

Descending limb of the loop of Henle

Answer 24

Permeable only to water, and the medulla has an ever-increasing osmolarity as the descending limb travels deeper into it –> interstitial concentration favors outflow of water from descending limb, which is reabsorbed into the vasa recta.

Question 25

Countercurrent multiplier system

Answer 25

Together, the vasa recta and nephron –> means that the flow of filtrate through the loop of Henle is in the opposite direction from the flow of blood through the vasa recta.

Question 26

Descending limb of loop of Henle

Answer 26

Permeable to salts and impermeable to water.

Maximizes salt reabsorption by taking advantage of decreasing medullary osmolarity

Question 27

Diluting segment

Answer 27

Loop of Henle becomes thicker at the transition from inner to outer medulla –> cells lining the tube are larger –> contain mitochondria which allow reabsorption of sodium and chlordie by active transport.
The only portion of nephron that can produce urine that is more dilute than the blood.

Question 28

Distal convoluted tubule (DCT)

Answer 28

Responds to aldosterone, which promotes sodium reabsorption –> because sodium ions are osmotically active particles, water will follow the sodium, concentrating the urine and decreasing its volume.
Also a site of waste product secretion

Question 29

Collecting duct

Answer 29

Responsive to both aldosterone and antidiuretic hormone (ADH or vasopressin). Collecting duct almost always reabsorbs water, but amount is variable.

Question 30

Osmotic prssure

Answer 30

The “sucking” pressure that draws water into the vasculature caused by all dissolved particles.

Question 31

Oncotic pressure

Answer 31

The osmotic pressure that is attributable to dissolved proteins specifically.

Question 32

Bicarbonate buffer system and kidneys

Answer 32

The kidneys are able to selectively increase or decrease the secretion of hydrogen ions and bicarbonate. When blood pH is too low, the kidneys excrete more hydrogen ions and increase reabsorption of bicarbonate, resulting in higher pH. and vice versa.

Question 33

What are the layers of the skin starting from the deepest layer and working outward

Answer 33

Hypodermis (subcutaneous)
Dermis
Epidermis

Question 34

Layers of the epidermis from superficial to deep

Answer 34

Come, Let's Get Sun Burned
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale

Question 35

Stratum basale

Answer 35

Contains stem cells and is responsible for proliferation of keratinocytes, the predominant cells of the skin,t hat produce keratin.

Question 36

Stratum spinosum

Answer 36

The cells become connected to each other; also the site of Langerhan’s cells

Question 37

Stratum granulosum

Answer 37

Keratinocytes die and lose their nuclei

Question 38

Stratum lucidum

Answer 38

Only present in thick, hairless skin, such as the skin on the sole of the foot or the palms, and is nearly transparent.

Question 39

Stratum corneum

Answer 39

Contains up to several dozen layers of flattened keratinocytes, forming a barrier that prevents invasion by pathogens and that helps to prevent loss of fluids and salts.

Question 40

Calluses

Answer 40

Form from excessive keratin deposition in areas of repeated strain due to friction; they provide protection to avoid damage in the future

Question 41

Melanocytes

Answer 41

A cell type derived from neural crest cells and found in the stratum basale –> they produce melanin, a pigment that serves to protect the skin from DNA damage caused by ultraviolet radiation

Question 42

Langerhans cells

Answer 42

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

Question 43

Layers of the dermis

Answer 43

Papillary and reticular layer

Question 44

Papillary layer

Answer 44

Upper layer (right below epidermis) of dermis, which consists of loose connective tissue

Question 45

Reticular layer

Answer 45

Below the papillary layer: contains sweat glands, blood vessels, and hair follicles

Question 46

Merkel cells (discs)

Answer 46

Sensory receptors present at the epidermal-dermal junction –> connected to sensory neurons and responsible for deep pressure and texture sensation within the skin.

Question 47

Meissner’s corpuscles

Answer 47

Respond to light touch

Question 48

Ruffini endings

Answer 48

Respond to stretch

Question 49

Pacinian corpuscles

Answer 49

Respond to deep pressure and vibration

Question 50

Hypodermis

Answer 50

Layer of connective tissue that connects the skin to the rest of the body

Question 51

Brown fat

Answer 51

Present especially in infants: has a much less efficient electron transport chain, which means that more heat energy is released as fuel is burned