32-BodyTemp Flashcards Preview

Nsci > 32-BodyTemp > Flashcards

Flashcards in 32-BodyTemp Deck (33)
Loading flashcards...
1

homeothermic

organism that regulates body temperature internally (eg humans)

2

poikilothermic

organism that regulates body temperature externally (eg reptiles)

3

primary source of heat loss

skin

4

secondary source of heat loss

lungs

5

primary source of heat production

cellular metabolism

6

sympathatic vasomotor response to decrease in environmental temperature

NE -> alpha adrenergic R -> vasoconstriction of cutaneous arterioles

7

sympathatic vasomotor response to increase in environmental temperature

ACH ->
-> vasodilation of cutaneous arterioles
VIP ->

8

VIP

vasoactive intestinal peptide

9

sympathetic effector of sweating

ACH -> incr sweat production

10

endocrine effector of cellular metabolism

thyroid hormone -> incr cellular metabolism -> incr heat production

11

neural effector of shivering-induced thermogenesis

ACH (not sympathetic) -> asynchronous skeletal muscle contraction (both extensors and flexors)

12

neural effector of BAT thermogenesis

postganglionic sympathetic: NE -> beta-3 adrenergic R -> incr in UCP

13

endrocrine effector of BAT thermogenesis

thyroid hormone

14

UCP

uncoupling protein
uncouples glucose oxidation from ATP production, produces heat instead

15

fiber type of cold receptors

A-delta

16

fiber type of warm receptors

C

17

cold transient receptor potential (TRP) channel in periphery

TRPM8 - DRG and trigeminal, menthol, <27 deg C

18

heat transient receptor potential (TRP) channel in periphery

TRPV3 - keratinocytes, DRG (low), brain and tongue, 33-40 deg C

19

Peripheral pathway of pain and temperature

spinothalamic tract

20

Peripheral pathway for thermoregulation

spino-parabrachial pathway

21

Site of thermoregulation control in hypothalamus

Anterior hypothalamus/preoptic area

22

heat transient receptor potential (TRP) channel in hypothalamus

TRPV4 - found in OVLT and medial preoptic; responds to 25-35 deg C, osmolality

23

Fever produced by

endogoneous pyrogens, released by macrophages in response to bacterial or viral particles

24

endogenous pyrogens - examples

cytokines: interleukin-1,-6, and tumor necrosis factor alpha

25

Endogenous pyrogens act on

neurons in anterior hypothalamus / preoptic area

26

Mechanism of action of pyrogens

act on cytokine receptors in AH/POA -> incr. induction of COX-2 -> incr. formation of prostaglandins (esp. PGE_2)

27

COX-2

cyclooxygenase-2, induced by pyrogens acting on cytokine receptors, leads to prostaglandin formation

28

Mechanism of NSAIDs in reducing fever

NSAIDs = non-steroidal anti-inflammatory drugs
Block COX-2 activity -> decr. PGE_2

29

Cytokines cross blood brain barrier via

circumventricular organs:
- median eminence
- area postrema
- pineal
- subfornical organ
*-* organum vasculosum of the lamina terminals (OVLT) - located near POA of hypothalamus

30

OVLT

organum vosculosum of the lamina terminals (OVLT) - site of BBB crossing of cytokines