Anatomy and physiology – HUB1019F
Homeostasis
What is physiology - The study of functions of living things
What is homeostasis?
Homeostasis refers to the process by which living organisms maintain a stable internal
environment, even when the external environment changes.
A dynamic steady state
Set point:
The physiological value around which the normal range fluctuates
A normal range:
The restricted set of values that is optimally healthful and stable
Intercellular fluid
Fluid within cells (called cytosol)
Extracellular fluid:
Fluid outside of cells – it is the body’s internal environment
Interstitial fluid:
Fills the narrow spaces between cells of tissues
Blood plasma -ECF within blood vessels
Lymph plasma - ECF within lymphatic vessels
Cerebrospinal fluid - ECF in and around the brain & spinal cord
Synovial fluid - ECF in joints
Aqueous humor & vitreous body - ECF of the eyes
Homeostasis is important for cell function
• Proteins require a specific conformation for efficient function and if the shape
is lost the protein cannot function
• This is because proteins can ONLY function in favorable conditions
• Proteins become DENATURED when in an unfavorable condition
, The nervous system regulates homeostasis by sending electrical signals (nerve impulses)
to organs – rapid changes
The endocrine system secretes hormones that maintain homeostasis – slow changes
Negative feedback
A mechanism that reverses a deviation from the set point & maintains body parameters
within their normal range
3 basic components:
1. Receptor – monitors a physiological value and then reports to the control center
2. Control center – compares values to their normal range (the brain). It evaluates
the input it receives from the receptors & generates output commands
3. Effector – causes a change to reverse the situation and return value to normal
range. It produces the response
Stimulus – a change in the internal or external environment.
Receptor picks up a stimulus
- Output shuts off the original stimulus or reduces its intensity
- Causes variable to change in a direction opposite to the initial change
- Controls processes that require continuous adjustments within narrow ranges
Positive feedback
A process where the output of a system amplifies or reinforces the initial stimulus,
leading to a self-reinforcing cycle that moves the system further from its original state
or equilibrium
Homeostasis
What is physiology - The study of functions of living things
What is homeostasis?
Homeostasis refers to the process by which living organisms maintain a stable internal
environment, even when the external environment changes.
A dynamic steady state
Set point:
The physiological value around which the normal range fluctuates
A normal range:
The restricted set of values that is optimally healthful and stable
Intercellular fluid
Fluid within cells (called cytosol)
Extracellular fluid:
Fluid outside of cells – it is the body’s internal environment
Interstitial fluid:
Fills the narrow spaces between cells of tissues
Blood plasma -ECF within blood vessels
Lymph plasma - ECF within lymphatic vessels
Cerebrospinal fluid - ECF in and around the brain & spinal cord
Synovial fluid - ECF in joints
Aqueous humor & vitreous body - ECF of the eyes
Homeostasis is important for cell function
• Proteins require a specific conformation for efficient function and if the shape
is lost the protein cannot function
• This is because proteins can ONLY function in favorable conditions
• Proteins become DENATURED when in an unfavorable condition
, The nervous system regulates homeostasis by sending electrical signals (nerve impulses)
to organs – rapid changes
The endocrine system secretes hormones that maintain homeostasis – slow changes
Negative feedback
A mechanism that reverses a deviation from the set point & maintains body parameters
within their normal range
3 basic components:
1. Receptor – monitors a physiological value and then reports to the control center
2. Control center – compares values to their normal range (the brain). It evaluates
the input it receives from the receptors & generates output commands
3. Effector – causes a change to reverse the situation and return value to normal
range. It produces the response
Stimulus – a change in the internal or external environment.
Receptor picks up a stimulus
- Output shuts off the original stimulus or reduces its intensity
- Causes variable to change in a direction opposite to the initial change
- Controls processes that require continuous adjustments within narrow ranges
Positive feedback
A process where the output of a system amplifies or reinforces the initial stimulus,
leading to a self-reinforcing cycle that moves the system further from its original state
or equilibrium
