Homeostasis Flashcards
Define homeostasis
Maintenance of a constant internal environment despite external changes; a system in dynamic equilibrium
What are the 8 human functional characteristics?
- Maintaining boundaries
- Movement
- Responsiveness
- Digestion
- Metabolism
- Excretion
- Reproduction
- Growth
What are the 5 human survival needs?
- Nutrients
- Oxygen
- Water
- Normal body temperature
- Appropriate atmospheric pressure
What are the 3 components of a homeostatic control system?
- Receptor
- Control centre
- Effector
What is the function of the receptor?
Detects changes in the environment and informs the control centre via the afferent pathway
What is the function of the control centre?
Receives information and determines what the response will be
What is the function of the effector?
Decides how the response is executed by receiving information from the control centre via the efferent pathway
What is the afferent pathway?
Stimulus –> Receptor –> Control centre
What is the efferent pathway?
Control centre –> Effector –> Response
How does negative feedback work?
- When a stimulus causes conditions to change, the effectors counteract this change to reduce/stop it
- When the desired level has been reached, negative feedback shuts off the original stimulus to maintain homeostasis
Give 5 examples of negative feedback mechanisms
- Thermoregulation
- Blood pressure
- Blood glucose
- Hunger physiology
- Exercise
Describe the process of thermoregulation
Stimulus - external temperature decreases
Receptor - thermoreceptors in hypothalamus and skin
Control Centre - hypothalamus
Effectors - muscles, organs and glands
Response - vasoconstriction, increase in cellular metabolism, shivering
Describe the process of maintaining blood pressure
Stimulus - blood pressure increases
Receptor - pressure receptors in carotid arteries
Control Centre - medulla
Effectors - heart muscle
Response - HR decreases so pressure is reduced
How does positive feedback work?
When a stimulus causes conditions to change, positive feedback increases the effect of the stimulus so that the reactions occurs at a faster rate
Give 4 examples of positive feedback mechanisms
- Blood clotting
- Childbirth
- Breastfeeding
- Menstrual cycle
Describe the process of childbirth
Stimulus - baby moving further down birth canal
Receptor - pressure receptors in cervix
Control Centre - hypothalamus
Effector - posterior pituitary gland
Response - more oxytocin is released, causing the uterus to contract more vigorously to push the baby out
What is anatomy?
The study of body shape and structure
What is physiology?
The study of bodily functions
What is cytology?
The study of plant and animal cells
What is epidemiology?
The study of the spreading and incidence of diseases
What is metabolism?
The chemical processes that occur in the body
What is histology?
The study of tissue structure
What is anabolism?
Synthesis of complex molecules
What is catabolism?
Breaking down of complex molecules
