Homeostasis Newest

7/30/2019 Homeostasis Newest

1/17


2/17

Keeping the internal environment of the body in

a Steady state (relatively constant) condition,despite changes in the external environment.

It is controlled by feedback mechanisms -cycle ofevents in which the status of a body condition is

continually monitored, evaluated, changed, re-

monitored, re-evaluated, etc.


3/17

metabolic reactions are controlledby enzymes

enzymes work best in a narrow

range of temperature & pH only important to keep internal

environment as steady as possible


4/17

Negative feedback mechanisms (used bymost of the body's systems) are callednegative because the information caused bythe feedback causes a reverse of the

response.

Positive feedback mechanism is used in somecases. Input increases or accelerates the

response.


5/17

Negative feedback occurs in a biochemicalpathway where the products of the reactioninhibit production of the substance/enzymethat controlled their formation.


6/17

Rise above

normal value

Fall below

normal value

normal

value

Corrective

Mechanism

Corrective

Mechanism

NEGATIVEFEEDBACK

MECHANISM

normal

value

negative

feedback

negative

feedback


7/17

It occurs when the accumulation of theproduct stimulates production of anenzyme/hormone responsible for thatproduct's production.

In other words, information produced by thefeedback increases and accelerates theresponse.


8/17

Kidneys: regulate water &mineral salts concentration

Skin: regulate body

temperature Liver & Pancreas: regulate

blood glucose level

Blood vessel: coagulation

Womb: Parturition

kidney

liver

pancreas+

skin

tissue

cells

blood


9/17

Regulate water potential inTissue Fluid

Organ involved: KIDNEYS


10/17

Normal Water

Content in Blood

After Sweating

Concentrated

Blood

Largerproportion of

water is

reabsorbed

ConcentratedUrine is

produced


11/17

Normal Water

Content in Blood

After Drinking

Diluted Blood

Smallerproportion of

water is

reabsorbed

Diluted Urineis produced


12/17

After having a very salty meal

produce concentrated urine to removeexcess salts in solution form

extra water is needed to be excreted along

with the excess salts

sensation of thirst (drink more water to

compensate for the water loss)


13/17

controlled by Negative feedbackmechanism

controlled by insulin secreted from

the islets of Langerhans in pancreas Diabetes - malfunction of pancreas

(does not secrete enough insulin)


14/17

Liverconverts

glycogen to

glucose

normal blood

glucose level

Blood glucose

level fallsSoonafter a

meal

Longafter a

meal Blood glucose

level rises

normal blood

glucose level

Too

High

Too

Low

Pancreas

secretes

insulin

Pancreas

secretes lessinsulin

Livercoverts

glucose to

glycogen


15/17


16/17


17/17

FIN ^_^

Homeostasis Newest

Documents