Task 7 - Hunger, Thirst, Hormones

Question 1

Osmotic thirst

Answer 1

• desire to ingest fluids that are stimulated by a higher concentration of solute (like salt - NaCL) in the extracellular fluid, which is reducing intracellular fluid
• By sweating and urinating which makes us lose more
• By ingesting lots of salty food

Question 2

Osmosensory neurons

Answer 2

located in Hypothalamus and detect concentration of extracellular fluid

• Balloon or shrink as concentration changes
• Opens/ closes special ion channels causing changes in membrane potential that track concentration
• Information passed on resulting in thirst through hormone release

Question 3

Hypovolemic thirst

Answer 3

• desire to ingest fluids stimulated by a reduced volume of extracellular fluid that contain water and solutes
• By losing blood/ vomiting or diarrhea
• No change in solute concentration in neither intra- nor extracellular fluid so no osmotic pressure
• Blood vessels that would normally be full and stretched no longer contain full capacity -> blood pressure drops -> thirsty hungry for salty food

Question 4

Baroreceptors

Answer 4

pressures receptors heart

-detects it in major blood vessels and heart

Question 5

Baroreceptor reflex

Answer 5

change in blood pressure
signals the medulla
creators thirst and salt hunger

Question 6

Ghrelin

Answer 6

• stomach
• hunger
• only hormone in peripheral system

Question 7

CCK

Answer 7

released in response of fat

Question 8

peptide yy (PYY)

Answer 8

release proportionate to the amount of calories you consume

Question 9

Leptin

Answer 9

• fat cell

- more fat stored=more leptin, so body knows how fat it is

Question 10

Leptin & fat people

Answer 10

fat ppl have a lot of leptin but they have become resistent to effects of leptin

Question 11

Hormones cant cross blood brain area sooooo

Answer 11

part of hippocampus -> arcuate nucleus

-» hormones interact with nucleus/ interact with brain

Question 12

vasopressin

Answer 12

from pituitary gland signals to kidney

-to reabsorb the water back to blood and not to bladder to make urine -» helps to conserve

Question 13

ENERGY METABOLISM

cephalic phase

Answer 13

PREPATORY PHASE

• Begins with sight/smell/thought of food
• Ends with food starting to be absorbed into bloodstream
• High release of insulin in anticipation of glucose arrival in the blood, low glucagon

Question 14

ENERGY METABOLISM

Digestive phase

Answer 14

food entering stomach causes release of gut hormones stimulates pancreas to release insulin

Question 15

ENERGY METABOLISM

Absorptive phase

Answer 15

• low glucagon, high insulin levels in blood
• Period where energy absorbed into bloodstream meets body’s immediate energy needs
• Glucodetectors in liver detect glucose entering bloodstream, signal pancreas to release insulin
• Minimise increasing levels of bloodborne fuels by using, storing them
• When rapid weight gain: straight back to cephalic phase

Question 16

Fasting phase

Answer 16

• All of unstored energy from previous meal has been used and body is withdrawing energy from its reserves to meet immediate energy requirements
• High glucagon, low insulin levels in blood
• Glucose can’t enter most body cells, stops being primary fuel -> glucose for brain
• Release of free fatty acids from adipose tissue and convert them to ketones -> used by muscles as source of energy
• Ends with next cephalic phase

Question 17

Theories of Hunger and eating

Set point assumption

Answer 17

hunger (motivation to eat) in presence of energy deficit and eat to return to body’s optimal energy level (energy set point)
Problemo:
-Evolutionary: need to PREVENT energy deficit for survival, not react
-Fail to recognise factors such as taste, learning, social influences

Question 18

Theories of Hunger and eating

Positive incentive perspective

Answer 18

driven to eat by anticipated pleasure of eating (positive-incentive value)

Question 19

Theories of Hunger and eating

Settling points model of body weight/Leaky barrel model

Answer 19

body tends to drift around a natural settling point – the level at which the various factors that influence body weight achieve an equilibrium

Question 20

Posterior Pituitary

Answer 20

release of Hormone Vasopressin

Question 21

Basal Metabolism

Answer 21

consumption of energy by lifte-sustainable functions of body

Question 22

Glucodetectors/Glucostats

Answer 22

sensors in liver that detect bloody glucose level

Question 23

Fluid regulation

Answer 23

67% intracellular

33% extracellular (Blood plasma, cerebrospinal fluid, interstitiolfluid)

Question 24

Osmotic pressure

Answer 24

the force that pushes or pulls water across the membrane

Question 25

Isotonic solution

Answer 25

When cells are balanced = no osmotic pressure

Question 26

Hypertonic solution

Answer 26

when cells are not balanced