sleep + hunger

Question 1

1. What happens to peripheral blood vessels when body is too cold❄️
2. What happens to peripheral blood veins when body is too hot

Answer 1

1. Peripheral blood vessels constrict - moves blood to interior of body so that heat isn’t lost through skin
2. Peripheral blood vessels expand - moves blood closer to skin so body heat can dissipate into the surrounding air

Question 2

Need state is what we experience when our body temperature becomes _________; it pushes us to _________ ________

Answer 2

Need state - What we experience when our body temperature becomes uncomfortable; it pushes us to correct the problem

Question 3

water freely moves in & out of cells bc of _________. When we drink water - it lowers __________ of extracellular fluid, causing cells to expand

Answer 3

water freely moves in & out of cells bc of tonicity. When we drink water - it lowers tonicity of extracellular fluid, causing cells to expand

Question 4

What’s the difference between osmometric thirst & volumetric thirst

Answer 4

Osmometric - when ur thirsty in your mouth
Volumetric thirst - when there isn’t enough blood circulating in the body (hypovolemia) - heart 🫀 needs certain amount of blood to keep beating; people feel intense thirst after they lose a lot of blood bc of this

Question 4

1. What is renin
2. What does it do during hypovolemia (volumetric thirst)
3. how does the body react to renin’s actions during hypovolemia

Answer 4

1. Renin is an enzyme released by cell in the kidneys during blood loss that initiates chemical reaction
2. during hypovolemia, renin will meet up with the hormone angiotensinogen and convert it into angiotensin I → converts it to angiotensin II
3. body reacts by stopping urination (to retain saltwater), increasing blood pressure, making u super thirsty

Question 5

1. When blood levels are high, insulin stores blood glucose as _________.

I2. nsulin also causes fat to be stored as ________ in adipose (fat) tissue

Answer 5

1. When blood levels are high, insulin stores blood glucose as glycogen in the liver
2. Insulin also causes fat to be stored as trigylcerides in adipose (fat) tissue

Question 6

1.when blood glucose is low 📉, glucagon causes ________ to be broken down into __________

2. Glucagon also causes triglycerides to be broken down into _________________ (becomes energy for muscles) or ___________ (turns int glucose, is stored as brain energy)

Answer 6

1. blood glucose is low 📉, glucagon causes glycogen to be broken down into glucose
2. Causes triglycerides to be broken down into fatty acids (becomes energy for muscles) or glycerol (turns int glucose, is stored as brain energy)

Question 7

About 2 hours after a meal, body can only use _______ (made from fatty acids) for energy

Answer 7

About 2 hours after a meal, body can only use ketones (made from fatty acids) for energy

Question 8

What is….
⭑Ghrelin
⭑ CCK & GLP-1
⭑ Leptin

Answer 8

⭑Ghrelin - peptide released when stomach is empty (highest in blood plasma during breakfast lunch & dinner)
⭑ CCK & GLP-1 - Hormones that regulate release of digestive enzymes & insulin; entry into brain promotes satiety feeling
⭑ Leptin - correlate with amount of fat in the body; If fat cells grow, leptin increases. Leptin levels falling below some threshold leads to intense hunger

Question 9

What effect does the administration of these have on hunger levels?
⭑Ghrelin
⭑ CCK
⭑GLP-1
⭑ Leptin

Answer 9

⭑Ghrelin - exogenous administration of ghrelin increases hunger & food intake
⭑ CCK - Administration of CCK does NOT cause weight loss; only causes ppl to eat smaller portions more often
⭑ GLP-1 - Administration of GLP-1 agonists
reduce hunger and weight in people
⭑ Leptin - Leptin injections are really good for people who can’t produce leptin on their own (reduces hunger)

Question 10

1. What is hypoglycemia (glucoprivation)
2. What is lipoprivation caused by

Answer 10

1. hypoglycemia - When there’s dangerously low blood glucose levels, which can cause intense hunger
2. When there’s dangerously low levels of fat on the body or free fatty acids in the blood

Question 11

1. Stimulation the neurons that co-release the peptides AGRP and NPY (PVN neurons) in the Arcuate Nucleus of the Hypothalamus causes _________ __________.

Answer 11

Stimulation of the neurons that co-release the peptides AGRP and NPY – causes dramatic overeating. (Leptin and other satiety signals inhibit these neurons)

Question 12

what is Prader-Willi Syndrome? (think of Tarrare)

Answer 12

rare chromosomal abnormality in which up to 7 genes are deleted from chromosome 15 (including one that’s necessary for PVN neurons) .. between 2 and 8 years old, ppl develop heightened, permanent and painful sensation of hunger - feeling of starving to death.
Average life expectancy in the United States is 30; most die of obesity-related causes.

Question 13

How does the RYGB surgery for decreasing hunger work

Answer 13

the second part of small intestine (the jejunum) is cut and attached to the top of the stomach. The stomach is also stapled to make it much smaller.

Question 14

Explain cascade of effects that comes after lack of sleep (for rats) in regards to body weight

Answer 14

their body heat goes up, their body weight goes down, so they eat more

Question 15

what is microsleep

Answer 15

when people don’t get enough sleep for a long period of time, they fall asleep for brief episodes lasting several seconds, and they are perceptually ‘blind‘ and often unaware that they have fallen asleep.

Question 16

Dolphins 🐬🌈 never fully sleep. What does their brain do instead

Answer 16

different hemispheres take time sleeping at once

Question 17

Whot does andenosine do

Answer 17

Andenosine promotes relaxation and sleep

Question 18

What is economies of scale (has to do with body mass, brain mass, metabolic rate, etc)

Answer 18

large animals benefit from saving heat & more efficient distribution network so each cell doesn’t have to work as hard - sleep time is highly correlated with these variables
- ↑ body mass, ↑ brain mass, ↑ overall metabolic rate but ↓ metabolic rate per kg (or per cell), ↓ heart rate, ↑ life span, ↓ total sleep time, ↑ length of sleep cycles

Question 19

EEGS - measures brain activity during sleep by attaching electrodes to scalp.

What are the oscillations of the wave of someone in Beta activity (aroused state)

Answer 19

-Beta activity (13-30Hz) reflects high frequency & low amplitude oscillations

Question 20

In neuroscience class, you install an EEG on my head & it’s picking up synchronized low frequency & large amplitude brain activity in my brain. What stage of sleep am i in

Answer 20

Delta activity/slow wave sleep (<4 Hz)

Question 21

What do these measure for sleep:
EMG
EOG

Answer 21

EMG - measures muscle activity by attaching electrodes to chin
EOG - measures eye movements by placing electrodes near eyes

Question 22

1. What are distinct characteristics of REM sleep
2. What are the stages of sleep

Answer 22

1. desynchronized EEG activity, rapid eye movements, dreaming, muscle paralysis
2. REM sleep, non, rem 1, non rem 2, non rem 3

Question 23

Newborn humans sleep 16 hours a day (___% REM / ___% NREM).

Adult humans sleep 7 hours a day (___% REM sleep / ____% NREM).

Answer 23

Newborn humans sleep 16 hours a day (50% REM / 50% NREM).

Adult humans sleep 7 hours a day (25% REM sleep / 75% NREM).

Question 24

Explain the main theories for sleep
1. recover from physical or mental exertion
2. Brain Processing (learning and memory)
3. Waste removal

Answer 24

1. If this is true, amount of exercise & thinking time should = total sleep time (this theory doesn’t hold up)
2. sleep gives the brain oportunity to reorganize data & archive memories, there’s active processing of info & transferring it between areas with gene transcription
3. since total sleep time = body size; sleep is critical for waste removal (there is some evidence pointing to this one); seems that clearance of proteins & waste is almost nonexistent while awake but rly high during sleep

Question 25

Explain what the glymphatic system does when animals sleep

Answer 25

when animals sleep, astrocytes (glial cells in the brain) lose water & shrink in size —> increases total volume of intersistial space (between cells)—> promotes diffusion of cerebrospinal fluid through brain —> clears waste product

Question 26

What happens to a rat’s circadian rhythm if they’re in a room with consistently dim light

Answer 26

rats largely maintain circadian rythms but they drift to a 23 or 25 hour cycle

Question 27

1. what does the suprachiasmatic nucleus (SCN) of the hypothalamus regulate
2. What does the leisioning of this area do

Answer 27

1. it regulates circadian rhythms
2. lesioning of SCN dramatically alters length & timing of circadiam rythms, but does NOT change total amount of sleep

Question 28

Snoopy has a strong urge to sleep at 2am and 11am. What sleep syndrome does he maybe have (& mutation of which gene)

Answer 28

Delayed sleep phase syndrome - a mutation of a gene called per3 causes a 4-hour delay in rhythms of sleep and temperature cycles

Question 29

Charlie has a strong urge to fall asleep at 7pm and wake up at 4am. What sleep syndrome does he maybe have

Answer 29

Advanced sleep phase syndrome - a mutation of a gene called per2 (period 2) causes a 4-hour advance in the biological clock (rhythms of sleep and temperature cycles)

Question 30

What is the sleep molecule hypothesis

Answer 30

there is a build-up of many molecules in the interstitial fluid of the brain during waking hours. These molecules are generally cleared away during sleep. Some of these molecules promote drowsiness and sleep at high concentrations.

Question 31

list signaling molecules that promote wakefulness

Answer 31

Serotonin
Norepinephrine
Acetylcholine
Orexin
Histamine

Question 32

REMINDER not question: Neurons in the ventral lateral preoptic area (vlPOA) of the hypothalamus promote sleep.

Electrical stimulation of this area causes drowsiness and sometimes immediate sleep. Lesions suppress sleep and cause insomnia.
(flip for more info)

Answer 32

vlPOA neurons inhibit wake-promoting neurons. But this area receives inhibitory inputs from the same regions it inhibits.

This kind of reciprocal inhibition characterises a flip-flop circuit; both regions cannot be active at the same time and the switch from one state to another is fast.

Question 33

What is cataplexy

Answer 33

When complete muscle paralysis suddenly occurs when someone is awake. It is typically precipitated by strong emotional reactions or sudden physical effort (e.g., laughter, anger, excitability).