Chapter 10: Homeostasis

Question 1

Detrusor muscle

Answer 1

Muscular lining of the bladder

Question 2

Internal urethral sphincter

Answer 2

Consists of smooth muscle and is contracted in its normal state

Question 3

External urethral sphincter

Answer 3

Consists of skeletal muscle and is under voluntary control

Question 4

Micturition reflex

Answer 4

When the bladder is full, stretch receptors convey to the nervous system that the bladder requires emptying; parasympathetic neurons fire; detrusor muscle contracts which causes internal sphincter to relax

Question 5

Proximal Convoluted Tubule

Answer 5

Amino acids, glucose, water-soluble vitamins, and the majority of salts are reabsorbed along with water; almost 70% of filtered sodium will be reabsorbed here; filtrate remains isotonic to the interstitium as other solutes and large amounts of water are reabsorbed; site for secretion of hydrogen ions, urea, ammonia, and potassium ions

Question 6

Loop of Henle

Answer 6

Descending limb of the loop of Henle - permeable only to water
Ascending limb of the loop of Henle - only permeable to salts (Na+, Cl-) and impermeable to water

Question 7

Diluting segment

Answer 7

At the transition from the inner to outer medulla; cells lining the tube are larger and contain large amounts of mitochondria which allow the reabsorption of sodium and chloride by active transport; only region of the nephron that can produce urine more dilute than blood; by the end of the loop of Henle, filtrate is more dilute and the volume has greatly decreased

Question 8

Distal convoluted tubule

Answer 8

Responds to aldosterone; site of waste produce secretion (active secretion of H+, K+, urea)

Question 9

Collecting duct

Answer 9

The final concentration of the urine depends largely on the permeability of the CD; responsive to both ADH and aldosterone; anything that does not leave the tubule by the end of the collecting duct will be excreted

Question 10

What does urine mostly contain?

Answer 10

Urea, uric acid, and excess ions (sodium, potassium, magnesium, and calcium)

Question 11

Oncotic pressure

Answer 11

Osmotic pressure that is attributable to dissolved protein specifically

Question 12

What is blood osmolarity usually maintained at?

Answer 12

290 mOsm

Question 13

Bicarbonate buffer system

Answer 13

The major regulator of blood pH

Question 14

How do the kidneys contribute to pH derangement

Answer 14

The kidneys are able to selectively increase or decrease the secretion of both hydrogen ions and bicarbonate; slower than the respiratory response

Question 15

What is the structure of the skin?

Answer 15

Hypodermis (subcutaneous layer), dermis, and epidermis

Question 16

Epidermis

Answer 16

Subdivided into strata

Question 17

What is the deepest stratum to shallowest?

Answer 17

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

Question 18

Stratum basale

Answer 18

Contains stem cells and is responsible for proliferation of keratinocytes - predominant skin cells that produce keratin

Question 19

Stratum spinosum

Answer 19

Cells become connected to each other; site of Langerhans cells

Question 20

Stratum granulosum

Answer 20

Keratinocytes die and lose their nuclei

Question 21

Stratum lucidum

Answer 21

Only present in thick hairless skin, such as skin on the soles of the foot or the palms; nearly transparent

Question 22

Stratum corneum

Answer 22

Contains up to several dozen layers of flattened keratinocytes, forming a barrier that prevents pathogen invasion and helps to prevent the loss of fluids and salt; hair projects above the skin and there are openings for sweat and sebaceous glands

Question 23

Keratin

Answer 23

Resistant to damage and provides protection against injury, water, and pathogens

Question 24

Calluses

Answer 24

Form from excessive keratin deposition in areas of repeated strain due to friction

Question 25

Melanocytes

Answer 25

Derived from neural crest cells and found in the stratum basale; produce melanin - a pigment that serves to protect the skin from DNA damage caused by UV radiation

Question 26

Langerhans cells

Answer 26

Special macrophages that reside within the stratum spinosum; capable of presenting antigens to T cells

Question 27

Dermis

Answer 27

Upper layer (right below the epidermis) is the papillary layer - consists of loose connective tissue; lower layer is the denser reticular layer; sweat glands, blood vessels and hair follicles originate in the dermis

Question 28

Merkel cells (discs)

Answer 28

Sensory cells present at the epidermal-dermal junction; connected to sensory neurons; deep pressure and texture sensation

Question 29

Free nerve endings

Answer 29

Respond to pain

Question 30

Meissner’s corpuscles

Answer 30

Light touch

Question 31

Pacinian corpuscles

Answer 31

Deep pressure and vibraion

Question 32

Ruffini endings

Answer 32

Stretch

Question 33

Hypodermis

Answer 33

Connects the skin to the rest of the body; layer of connective tissue

Question 34

Sweating

Answer 34

Cooling mechanism that is controlled by the sympathetic nervous system; postganglionic sympathetic neurons release ACh to promote the secretion of water with certain ions onto the skin

Question 35

Arrector pili

Answer 35

These muscle contract resulting in piloerection; this helps to trap a layer of heated air near the skin; arterioles that feed the capillaries of the skin constrict, limiting the quantity of blood reaching the skin

Question 36

Shivering

Answer 36

Requires a sizeable amount of ATP; significant portion of this ATP is lost as heat

Question 37

White fat

Answer 37

Insulates the body

Question 38

Brown fat

Answer 38

Much less efficient ETC therefore more heat energy is released as fuel is burned