wk1 / c3 (homeostasis)

Question 1

homeostasis:

Answer 1

Question 2

Homeostasis-

1st aspect of homeostasis-

controlled condition/ set point:

Answer 2

• Normal physiological range for the monitored variables within the body
  ie. blood glucose, blood pressure, ph of blood, body temp (these kinds of physiological processes)

Question 3

Homeostasis-

controlled conditions work at which levels?

(4)

Answer 3

• cellular
• tissue
• organ
• systems

leves

(homeostasis occurs in all these systems, and btw these systems as they interact)

Question 4

Homeostasis- stimulus

we have the controlled conditions occuring w/in our body all the time, however we are _

Answer 4

dynamic organisms

Question 5

homeostasis- stimulus

there are many biological conditions _

Answer 5

interacting within our bodies

Question 6

homeostasis- stimulus

we are also _ and _ with the external environment

Answer 6

responding and interacting with the external environment

Question 7

homeostasis- stimulus

stimulus:

Answer 7

any external or internal factor which changes the controlled conditions

Question 8

homeostasis- stimulus

when we change the controlled condition we are?

Answer 8

disrupting homeostasis

(by either increasing or decreasing that variable beyond the normal physiological range)

Question 9

homeostasis- stimulus

examples of stimuli to the body?

(5)

Answer 9

Question 10

homeostasis-

1st key component of homeostasis

what detects change to homeostasis?

Answer 10

a receptor

Question 11

homeostasis-

1st key component of homeostasis

receptor:

Answer 11

Question 12

homeostasis- receptor

1st key component of homeostasis

example

nerve cell detecting changes in?

Answer 12

temperature

Question 13

homeostasis- receptor

1st key component of homeostasis

example

nerve cell detecting changes in?

Answer 13

pressure

Question 14

homeostasis- receptor

1st key component of homeostasis

example

nerve cell detecting changes in?

Answer 14

chemicals

ie. in our mouths, diff tastes

Question 15

homeostasis- receptor

1st key component of homeostasis

how is info picked up by receptors, in 2 diff ways?

Answer 15

specialise nerve cells pick up change, via a nerve impulse (fast acting) ie. pics on left

or

a specialised receptor protein which sits in the surface of the cell, that can detect the change and send a chemical signals (slow acting)

ie. pic on right

Question 16

homeostasis -

2nd key component

control centre:

Answer 16

Question 17

homeostasis- control centre

2nd key component of homeostasis

in most cases the control center is?

Answer 17

the brain

(although there are exceptions to this rule)

Question 18

homeostasis- control centre

2nd key component of homeostasis

process of the control centre?

pic

Answer 18

Question 19

homeostasis- control centre

2nd key component of homeostasis

input flowing to the control center is also called?

Answer 19

afferent pathway

Question 20

homeostasis- control centre

2nd key component of homeostasis

output flowing away from the control centre is called?

Answer 20

efferent pathway

(once the brain processes the info and sends out instructions to the effector, or because its travelling away from the brain)

Question 21

homeostasis- control centre

2nd key component of homeostasis

how is info sent to the control centre?

Answer 21

again by

nerve impulses (fast acting)

or

chemical signals (slower acting)

ie. hormones or other small chemical molecules

Question 22

what is the purpose of sending info to the control centre?

Answer 22

to try and elicit a response

Question 23

homeostasis - 3rd key

component

effector:

Answer 23

Question 24

homeostasis - 3rd key

component

effector-

what is this example?

Answer 24

molecules that are sensing, sitting on the surface of an organ,

that are receiving a chemical signal (hormone or diff chem mole)

or

it could this could happen by a specialised nerve cell that receives that nerve impulse

Question 25

example of a nerve impulse

Answer 25

nerve impulse contracts one of the muscles, which is attached to one of the hair bulbs, so that the hair stands up on the surface of the skin

Question 26

example of recieving a signal in the lungs

Answer 26

to change the size of the airways within our lungs, to either dialate or constrict some of the air passage ways

Question 27

example of signal to heart

Answer 27

changes to the muscles of the heart, which can cause the heart to beat faster or slower

Question 28

explain all example of effectors here

Answer 28

* skin, muscles att constrict to stand up hairs * lungs, open or close airways * heart, muscles contract to beat faster or slower * blood vessels, dialate or contract to speed up or slow blood flow * eye, pupil dialate * liver, changes so other chem may be secreted * kidney, changes to retain or release more water * adrenal gland, release chem hormones that effect other tissues and organs of the body

Question 29

effector is dependant on what the _ is and which biological pathway has been \_

Answer 29

stimulus disrupted from homeostasis

Question 30

summary of homeostasis | (occurs as a loop)

Answer 30

1. **stimulus** - disrupts homeostasis, by increasing or decreasing.. 2. **controlled conditions** - that are constantly monitored by.. 3. **receptors** - that send (thu afferent pathway/input) nerve signals or chemical impulses to a.. 4. **control centre**- that recieves the input and sends (thu efferent pathway/output) nerve impulses or chemical signals (such as hormones) to ... 5. **effectors**- detect msg sent, that bring about a change so that we get a .. 6. **response-** that alters the controlled condition we **return to homeostasis** only when that response brings the controlled condition back to normal

Question 31

summary of homeostasis diagram

Answer 31

Question 32

homeostasis- homeostasis occurs as a loop, called a?

Answer 32

**feed back loop** 2 types - positive - negative feedback loops

Question 33

feedback loop- ## Footnote **positive feedback loop:**

Answer 33

when the response enhances or intensifies the stimulus (the only way to stop that loop is for the stimulus to be removed)

Question 34

feedback loop- ## Footnote **negative feedback loop:**

Answer 34

when the response reverses the stimulus (and brings the controlled condition back into its normal range)

Question 35

feedback loop- **negative feedback loop:** (these types of fb loops are extremely common, and govern a number of biological processes that occur throughout the body **example blood pressure**

Answer 35

1. stimulus- (may be stress) disrupts homeostasis by **increasing**.. 2. controlled condition - of **blood pressure** 3. receptors- **baroreceptors** (specialised receptors that are in the **lining of the blood vessels**) in certain blood vessels, the detection of the blood pressure is then **sent via afferent** pathways/input **as a nerve impulse** to the .. 4. control center- in this case the **brain**, the brain processes that information, then sends an **output/efferent pathway** via **nerve impulses** again to the .. 5. effectors- in this ex. **blood vessels and the heart** 6. response- the blood vessels **dialate,** let more blood thu, that will **decrease the blood pressure** as well as the **heart rate** we return to homeostasis when the responses bring the **blood pressure back to normal** (may not happen immediately, may need to go though the loop a few times, depend on the the particular change we are taking about and the intensity of the stimulus)

Question 36

feedback loop- negative feedback loop: diagram

Answer 36

Question 37

feedback loop- positive feedback loop: **example birth contractions** (less common as opposed to neg)

Answer 37

1. stimulus- the contractiof the wall of the uterus, that force the babies head and body into the cervix, means increase in controlled condition 2. controlled condition- stretching of the cervix 3. receptors- that detect this increase stretching of the cervix are the stretch sensive nerve cells in the cervix, they pick this change up, they send the info to the control centre via nerve impulses (afferent pathway/input) 4. control centre- the brain, interprets info, processes that info and sends via output/efferent pathway and releases oxytocin, travels in the blood stream to the .. 5. effectors- and it effects the muscles in the wall of the uterus, and causes them to start contracting more forcefully 6. response- babies body starts to stretch the cervix more continue to go round this loop, the increase stretching of the cervix causes the release of more oxytocin (so can see why its positive loop/more of the hormone, more stretching) the only way it ends is the interuption of the cycle (by baby being born, decreases the stretch of the cervix and breaks cycle)