Sleep And Internal Regulation

Question 1

Homeostasis

Answer 1

maintenance at a set point

Question 2

Allostasis

Answer 2

adaptive way body anticipates needs

Question 3

Types of temperature regulation

Answer 3

• Poikilothermic (exothermic): Body matches environment and external sources used to regulate temp. EG huddling together
• Homeothermic (endothermic): Internal mechanisms used, eg sweating. High rates of energy

Question 4

Why control body temp?

Answer 4

Pro: muscles benefit.
Con: high energy load

Question 5

Regulation is controlled by…

Answer 5

Regulation controlled by hypothalamus. POA = physiological, AH = behavioural

Question 6

Angiotensin II

Answer 6

constrict blood vessels and increase BP

Question 7

Vasopressin

Answer 7

antidiuretic, compensates for decreased water volume

Question 8

How can thirst be triggered

Answer 8

Osmotic and hypovolemic

Question 9

Osmotic thirst

Answer 9

Osmotic (high conc of solute creates osmotic pressure

Question 10

Hypovolemic

Answer 10

low fluid volume, causes a drop in BP to initiate production of vasopressin

Question 11

Signal to stop hunger

Answer 11

Distension of stomach

Question 12

Vagus nerve

Answer 12

conveys info about stretching to brain

Question 13

Splanic nerves

Answer 13

convey info about nutrient contents

Question 14

Duodenum

Answer 14

site of nutrient absorption. Releases hormone CCK which regulates hunger.

Question 15

Arcuate nucleus

Answer 15

receives information re hunger.

Contains two neurons: NPY (increase, inhibit of paraventricular nucleus) and POMC (suppress, deliver excitation to paraventricular nucleus).

Question 16

Ghrelin

Answer 16

hunger hormone – release from stomach into blood stream, influences hypothalamus, inhibited by leptin.

Question 17

Lateral hypothalamus role

Answer 17

Hunger

Question 18

Paraventricular nucleus

Answer 18

Satiety

Question 19

Endrogenous biological rhythms

Answer 19

Circadian, infradian, circannual, ultradian

Question 20

Zeitgeber

Answer 20

Stimulus that resets circadian rhythm. Primary is sunlight

Question 21

Suprachiasmatic Nucleus (SCN)

Answer 21

main control centre. Located above optic chiasm, internal timekeeper and receives input from hypothalamic path

Question 22

Retinohypothalamuc path

Answer 22

light resets the SCN via branch in optioc nerve

Question 23

Mêla Papin

Answer 23

Special ganglion cells have their own photopigment (melanospin). These cells do not require input from photoreceptors (rods/cones)

Question 24

Proteins for SCN

Answer 24

• Clock and BMAL1: Transcriptors for PER and CRY
• PER and CRY inhibit CLOCK and BMAL1
• PER and CRY broken down resulting in increased transcription

Question 25

Melatonin

Answer 25

released by pineal gland, receives input from and affects activity of SCN

Question 26

Wakefulness maintained by

Answer 26

ARAS

Question 27

Wakefulness - areas involved

Answer 27

Pons, locus coeruleus, raphe nuclei, PAG, thalamus, hypothalamus

Question 28

Transmit wakefulness by

Answer 28

Midbrain to cortex via thalamus, midbrain to cortex via lateral hypothalamus and basal forebrain

Question 29

ARAS - information from

Answer 29

Receives input from sensory systems. Both paths most active while awake.

Question 30

Sleep inhibition relies on

Answer 30

ARAS. Ventrolateral preoptic area sends inhibition.

Question 31

Regulation of sleep-wake cycle

Answer 31

ARAS, SCN, Pineal gland and melatonin

Question 32

ARAS maintains wake via

Answer 32

two pathways (M > C (T), M > C (Lat hyp, bas fore)

Question 33

Stages of sleep

Answer 33

Understood VIA EEG, combines measures of heart rate, resp rate, BO levels, eye and leg movements
• Stages of sleep: NREM 1-4 sleep, REM (paradoxical sleep).

Question 34

Activation-synthesis hypothesis:

Answer 34

Spont PGO waves activate cortex, and forebrain attempts to synthesise and interpret these waves

Question 35

Clinico-Anatomical hypothesis:

Answer 35

Activity is high in parietal cortex (visual-spatial) and hypothalamus/amygdala (emotional/motivation). Activity is low in primary visual cortex, auditory cortex and primary motor cortex.