homeostasis

Question 1

what is homeostasis?

Answer 1

maintaining relative constant environment in the body.

maintaining internal equilibrium by adjusting its physiological processes.

Question 2

explain how sweating maintains homeostasis and what excessive sweating can do.

Answer 2

its is released to cool the body from the outside.

but too much sweat causes blood volume to decrease = drop in BP and disrupts homeostasis

Question 3

how does increased heart rate maintain homeostasis?

Answer 3

heart rate increases because there is a need for increased blood flow in the body. once the heart rate increases so does BP

Question 4

how is thirst a signal of homeostasis?

Answer 4

increase in water intake is signaled because they need to replenish water that is lost in sweat

Question 5

what is the set point?

Answer 5

the ideal normal value of a variable.

Question 6

what is the normal range?

Answer 6

the range of fluctuation from the set point that is normal

Question 7

what is the set point and normal range for body temp?

Answer 7

set point = 37 degrees
normal range = 36.5 to 37.5

Question 8

how do the organ systems help maintain homeostasis?

Answer 8

• controls the internal environment
• allows communication between cells, tissues and organ systems
• NS and endocrine system gather sensory info form internal and external environment to send signals throughout the body = maintain homeostasis

Question 9

what are the 3 components of the feedback system?

Answer 9

receptor = monitors the value of a variable

control center = establishes set point

effector = can change the value of the variable

Question 10

what is the stimulus

Answer 10

causes the “change” like deviation from set point that’s detected from the receptor

Question 11

what is the response produced by

Answer 11

effector

Question 12

what are the two types of feedback systems?

Answer 12

negative and positive

Question 13

describe negative feedback system.

Answer 13

negative feedback only happens when the deviation from the set point is made smaller (resisted) aka bringing body back to normal level

1. stimulus - disrupts homeostasis by increasing or decreasing a controlled condition
2. the controlled condition is monitored by receptors
3. the receptors send nerve impulses to the control center (brain)
4. control center receives the input and provides nerve impulses or chemical signals to effectors
5. effectors bring a change or response that alters controlled condition
6. controlled condition is returned to normal = HOMEOSTASIS RETURNED!

Question 14

what are some examples of negative feedback?

Answer 14

body temperature
regulation of BP
blood sugar levels

Question 15

what is a positive feedback system?

Answer 15

when a deviation occurs and the response is to make the deviation greater

1. the stimulus disrupts homeostasis by increasing the controlled condition
2. the controlled condition is monitored by receptors
3. the receptors send nerve impulses to the control center (brain)
4. control center receives the input and provides nerve impulses or chemical signals to effectors
5. effectors bring a change or response that alters controlled condition
   !!DISTRUPTION!!
6. controlled condition is returned to normal after disruption = back to increased controlled condition

Question 16

what is an example of positive feedback? explain it.

Answer 16

childbirth

1. contractions of the wall of the uterus force baby head into cervix
2. increases stretching of the cervix (controlled condition)
3. receptors = stretch-sensitive nerve cells in the cervix send nerve impulses to the brain
4. the brain interprets the input and releases oxytocin
5. this causes the effectors (muscles of the uterine wall) to contract more forcefully
6. the response - baby’s body stretched the cervix more
   DISTRUCPTION = baby birth = decreases stretching = breaking positive feedback cycle
7. increased stretching of cervix causes the increased release of oxytocin = more cervix stretching = BACK TO INCREASED STRETCHING OF CERVIX CONDITION

Question 17

how can positive feedback lead to death?

Answer 17

in healthy humans leading away from homeostasis is unusual.

harmful positive feedback:
hemorrhage (dramatic loss of blood) leads to a decrease in BP and the heart cant pump blood b/c there isnt enough getting to it

Question 18

is BP during exercise non-homeostatic?

Answer 18

no, but the normal range can change temporarily depending on body situation

• increase in exercise = increase in BP
• blood flow and BP have direct corelation
• when exercising increase blood flow may be needed b/c of increase 02 and nutrient intake

THEREFORE: exercise = larger normal range b/c the body’s demands change so much

Question 19

what happens when you loose homeostasis?

Answer 19

disease
death - if disease isnt controlled in normal range = death

Question 20

describes what happens with the Acromegaly condition.

Answer 20

rare condition where the body produces too much growth hormone b/c of the loss of homeostasis, causing body tissues and bones to grow more quickly.

can be caused by a tumor in pituitary gland - pituitary gland controls homeostasis