3. integument physiology

Question 1

what are the 7 integument functions?

Answer 1

• protection
• immune defence
• sensing environment
• thermoregulation
• storage and excretion
• communication/camouflage
• selective permeability

Question 2

what are the 3 skin sensors?

Answer 2

• mechanoreceptors
• nociceptors
• thermoreceptors

Question 3

what are the 5 mechanoreceptors and what do they detect?

Answer 3

• Ruffini’s end organ or bulbous corpuscle – skin
  stretch.
• Krause end bulb or bulboid corpuscle–cold.
• Meissner’s corpuscle or tactile corpuscle – change in texture, slow vibrations.
• Pacinian corpuscle or lamellar corpuscle – pressure, fast vibrations.
• Merkel’s disc, a free nerve ending with discoid terminals – sustained touch and pressure.

Question 4

what are nociceptors?

Answer 4

free nerve endings that sense pain

Question 5

what are thermoreceptors?

Answer 5

free nerve endings that detect hot or cold

Question 6

what is homeostasis?

Answer 6

Maintenance of constant conditions within the body’s internal environment in face of disturbances.

Question 7

what does homeostasis need to balance?

Answer 7

• Concentration of water, salt and electrolytes.
• pH.
• Concentration of blood gases (O2 and CO2).
• Concentration of waste products.
• Responses to infection, injury, pain and emotional stress.
• temperature

Question 8

what percentage of water is in a total adult body mass?

Answer 8

60-65%

Question 9

how is water inputted into the body?

Answer 9

• free water intake (drinking)
• water in food
  -metabolic water

Question 10

How us water outputted in the body?

Answer 10

• urine
• faeces
• insensible losses- evaporation from skin and airway

Question 11

what are electrolytes?

Answer 11

minerals in the blood and other bodily fluids that carry an electrical charge

Question 12

What do electrolytes impact?

Answer 12

• water balance
• blood acidity (pH)

Question 13

how are electrolytes maintained?

Answer 13

by adjusting the water concentration detected by osmoreceptors in the hypothalamus

Question 14

what is acid-base homeostasis?

Answer 14

balance between acids and bases; constant hydrogen ion concentration [H+]

Question 15

what maintains and controls homeostasis?

Answer 15

Region of the brain called the hypothalamus

Question 16

what does the hypothalamus coordinate?

Answer 16

Coordinates activities of the autonomic nervous system (ANS) which are sympathetic, parasympathetic and enteric nervous systems

Question 17

what does the hypothalamus control?

Answer 17

major part of the endocrine system

Question 18

what does the hypothalamus detect?

Answer 18

osmolarity of the interstitial fluid in the brain via osmoreceptors

Question 19

what does the hypothalamus monitor?

Answer 19

brain temperature

Question 20

How does temperature homeostasis work?

Answer 20

• hypothalamus acts as a thermostat
• it receives nerve impulses from cold and warmth thermoreceptors (free nerve endings) within the skin
• also works by thermosensors within the hypothalamus and within the spinal chord, visceral organs and nasal/oral organs

Question 21

what is the normal body temperature for most species?

Answer 21

38C

Question 22

what do homeotherms use to thermoregulate?

Answer 22

metabolic heat

Question 23

what do poikilotherms use to thermoregulate?

Answer 23

external environment

Question 24

what is hypothermia?

Answer 24

below normal body temperature: when heat loss exceeds heat production

Question 25

what is hyperthermia?

Answer 25

above normal body temperature: when heat production exceeds heat loss. Can be physiological and pathological

Question 26

what is fever or pyrexia?

Answer 26

when the hypothalamic set point is reset to a higher temperature, this enhances leucocyte function to help fight infection

Question 27

is thermoregulation a positive or negative feedback mechanism?

Answer 27

negative

Question 28

With thermoregulation: what happens if our body temperature gets too high?

Answer 28

hypothalamus heat loss centre detects higher than set point temperature, this makes the blood vessels dilate and actives the sweat glands. Body temperature then decreases to a normal set point.

Question 29

With thermoregulation: What happens if our body temperature gets too low?

Answer 29

Hypothalamus heat-promoting centre detects lower body temperature, the blood vessels constrict and the skeletal muscles are activated: shivering begins. This increases body temperature to normal

Question 30

How do animals produce heat?

Answer 30

- By product of the metabolic process: all food energy is converted either directly or indirectly - exercise - eating - muscle contraction ( shivering thermogenesis) brown adipose tissue (non-shivering thermogenesis) - fever

Question 31

what is non-shivering thermogeneisis

Answer 31

increased heat production Bia increased metabolism

Question 32

what is non-shivering thermogenesis as a response to?

Answer 32

cold external factors

Question 33

what is non- shivering thermogenesis mediated via?

Answer 33

- increased thyroxine secretion (the hormone from the thyroid gland) - increased sympathetic (ANS) activity (norepinephrine) - increased metabolism of lipids in response to circulation cetecholamines (norepinephrine/epinephrine)

Question 34

what is brown adipose tissue

Answer 34

- A tissue predominately found in neonates as they have a large SA:V - pigs don't have any as they don't have a UCP1 Gene - present in small hibernating mammals in a adulthood - specific to mammals

Question 35

What is the structure of brown adipose tissue?

Answer 35

- they have a darker colour due to a higher density of mitochondria with cytochrome pigment - they have smaller lipid droplets then yellow adipose tissue - they have many lipid droplets compared to yellow adipose tissue

Question 36

where is brown adipose tissue located?

Answer 36

in the subcutaneous region between scapular and around kidney and myocardium

Question 37

what does brown adipose tissue do?

Answer 37

due to lipids being in close proximity to mitochondria it facilitates the rapid transfer of stored energy to heat energy

Question 38

What stimulates brown adipose tissue?

Answer 38

circulating catecholamines and norepinephrine secreted from sympathetic nerve endings

Question 39

What are the 3 ways animals lose heat?

Answer 39

- radiation - conduction and convection - evaporation

Question 40

how do animals lose heat by radiation?

Answer 40

when the body is warmer than the environment, it loses heat by emission of infra-red radiation

Question 41

how do animals lose heat by conduction and convection?

Answer 41

- directly from the body surface to cooler objects in contact with the animal - transfer of heat by warm air to cooler air

Question 42

how do animals lose heat by evaporation

Answer 42

ambient air is equal to or greater than body temperature: panting and sweating

Question 43

what is panting?

Answer 43

A number of pattern acts top increase heat loss through evaporation

Question 44

what are the 3 panting pattern acts?

Answer 44

- inflation and exhalation through the nose - inhalation through the nose and exhalation through the nose and mouth - inhalation through the nose and mouth and exhalation through the nose and mouth

Question 45

which species is sweating an important means of thermoregulation and from what glands?

Answer 45

- horses and cattle via apocrine sweat glands - primates via eccrine sweat glands

Question 46

where are sweat glands confined to in cats?

Answer 46

- paws - lips - chin - perineum

Question 47

which species have poor developed sweating?

Answer 47

dogs and pigs so have little use in thermoregulation

Question 48

What supplies blood to the skin?

Answer 48

cutaneous arteries

Question 49

In blood supply to skin what are the 3 plexus involved?

Answer 49

- deep or subcutaneous plexus ( terminal branches of the cutaneous arteries) - middle plexus - superficial plexus

Question 50

How is heat transferred within the body?

Answer 50

- heat transported by the blood - heat it is produced primarily in muscles and the liver - heat is lost through through skin and respiratory tracts as has very good blood supply with many small vessels close to the body surface - rise is core body temp increases blood flow to the skin - decrease in core body temp decrease flow