Homeostasis (PPT 1) [U2/ T1] Flashcards
What do cells need to survive?
- Energy
- Oxygen
- Nutrients
- Removal of wastes
- Water
- Warmth
Why do cells require energy & oxygen?
To drive respiration and photosynthesis
Why do cells require nutrients?
To drive chemical reactions
Why do cells require the removal of wastes?
The wastes are toxic to the cell
Why do cells require water?
Most chemical reactions occur within a solution
Why do cells require warmth?
Enzyme reaction rate
What does cellular respiration mean?
All chemical reactions that occur inside a living cell.
What is homeostasis?
The maintenance of a stable internal environment in the face of changes in either the external or internal environment.
What is a negtive feedback system?
- A stimulus response mechanism that acts to restore the original state.
- The response produced reduces the effect of the original stimulus. Therefore, having a negative effect on the stimulus.
What is a postive feedback system?
- Not as common in homeostatis because they lack a regulatory role.
- Invole those in which a stimulus causes a change that increases the effect of the initial stimulus (positive effect).
What are receptors?
Specilaised structures capable of responding to specific stimuli by initiating specific signals.
Interoreceptors detect…?
Internal stimuli
Exteroreceptors detect…?
External stimuli
Receptors recieve specialised sensory information that relates to what?
- Photo (light)
- Mechano (touch/ pressure)
- Chemo (chemicals)
- Thermos (temperature)
- Noci (pain)
State 2 facts about photo receptors.
- Common in animals
- Vary in complexity
- Light sensitive cells to complex eyes
State 2 facts about mechano receptors.
- Stimulus is anything that changes their shape
- Different types control all sorts of bodily functions
State 2 facts about chemoreceptors.
- Recieve specific chemicals in an internal & external environment
- Chemicals detected through taste and smell
State 2 facts about thermo receptors.
- Temperature is detected by thermoreceptors
- All animals have a optimum temperature
State 2 facts about pain receptors.
- Everywhere except the brain
- Have large receptive fields
- Detect chemicals released by damaged cells
What does an effector do?
Responde to the signal and brings the system back to a set point.
Name the 2 types of effectors and what they do
Muscles - contract or relax in response to neural stimuli
Glands - produce or don’t produce secreations (hormones)
