6A: Introducing Homeostasis

Question 1

Homeostasis is

Answer 1

the process of maintaining a stable internal body environment

Question 2

Homeostasis manages

Answer 2

body temperature, pH (acidity) levels, blood sugar levels, sodium and potassium concentration, fluid balance

Question 3

Ideal levels of homeostatic parameters

Answer 3

)tempreature (maintains optimal internal body tempreature (around 36.5-37.5) - increase and decrease of body sufrace area to cool down/warm up the body, shivering, goosebumps, sweating, etc are all body responses to cold/hot tempreatures
)pH (acidity level)(optimal pH of the blood is 7.35-7.45) - kidneys job
)blood sugar levels (blood sugar levels are maintained between 4.0 - 7.8 mmol/L) -
)sodium and potassium concentration (normal levels are 135 - 145 mmol/L for sodium and 3.5-5.0mmol/L for potassium)
)fluid balance

Question 4

Stimulus response model

Answer 4

(stimulus–>receptor–>modulator–>effector–>response)

Question 5

Stimulus

Answer 5

(a change in something in the internal (e.g. food in the body after eating) or external (e.g. tempreature) environment

Question 6

Stimulus is recognised by a

Answer 6

receptor

Question 7

thermoreceptor

Answer 7

recognizes temperature

Question 8

noicireceptor

Answer 8

recognizes pain

Question 9

baroreceptor

Answer 9

detects change in blood pressure

Question 10

chemreceptor

Answer 10

detects change in chemical concentration

Question 11

photoreceptor

Answer 11

detects change in light

Question 12

modulator

Answer 12

works out what to do based on the information it has received (e.g. hypothalamus (in the brain))

Question 13

the main modulator of homeostasis is

Answer 13

the hypothalamus

Question 14

effector

Answer 14

(is the part of the body that the modulator communicates with (e.g. sweat glands)

Question 15

response

Answer 15

is the response from this effector (e.g. sweating)

Question 16

example of stimulus response model when body gets hot

Answer 16

body gets hot, picked up by thermoreceptors, signal goes to hypothalamus which tells body to start sweating, hypothalamus tells sweat glands to start sweating, body begins to sweat

Question 17

TRUE OR FALSE: some receptors will act faster due to the risk/damage it will have on/to the body (e.g. pain receptors (nociceptors) will act faster than thermal receptors (thermoreceptors))

Answer 17

TRUE

Question 18

Types of Feedback systems

Answer 18

Positive feedback, negative feedback

Question 19

Negative feedback systems

Answer 19

occur when the response counters the stimulus.

Question 20

Enzymes are

Answer 20

protein molecules that speeds up or catalyses a chemical reaction

Question 21

TRUE OR FALSE: in negative feedback, the loop continues once the stimuli has been countered

Answer 21

FALSE

Question 22

An example of positive feedback is

Answer 22

pregnancy

Question 23

What is positive feedback

Answer 23

Positive feedback (very rare) occurs when the response does not counter the stimuli

Question 24

Stimulus response model of pregnancy/child birth

Answer 24

(stimulus (pressure in the cervix)–>receptor (nociceptors)–>hypothalamus?–>effector (pituitary gland secretes oxytocin)–>oxytocin detected by the uterus)–>REPEAT