The Human Nervous System Flashcards
What is homeostasis?
Regulation of internal conditions of a cell or organism to maintain optimum conditions for function, in response to internal and external changes
What is homeostasis important for?
Maintaining optimal conditions for enzyme action and all cell functions
How body controls exercise and eating
Exercise -> muscles get hotter
Eat -> blood sugar levels go up
Lose water and salt when sweat
What are some internal conditions controlled by homeostasis?
Body temperature
The water content of the body
Blood glucose concentration
Key features to control homeostasis
Receptors = detect changes known as stimuli
Coordination centres = receive and process information from receptors
Effectors = muscles and gland, restore conditions
Process of how your nervous system works
1) sensory receptor detects stimulus
2) sends electrical impulses along sensory neurones
3) impulse reaches CNS
4) brain coordinates response
5) sends impulses along motor neurones
6) gets to effectors
7) effectors respond
8) muscles respond by contracting OR glands respond by releasing chemical substances
Nervous system summed up
Stimulus -> receptor -> coordinator (CNS) -> effector
What three types of neurone are involved in reflexes
Sensory
Motor
Relay (connects sensory and motor)
How do reflexes work?
1) electrical impulse passes from receptor
2) travels along sensory neurone
3) arrives at CNS
4) passes along relay neurone
5) back along motor neurone
6) arrives at effector organ (muscle or gland)
Summary of reflex pathway
Stimulus -> receptor -> sensory neurone -> relay neurone -> motor neurone -> effector -> response
What happens when you touch something hot
1) Receptor in skin detects a stimulus (change in temperature)
2) Sensory neurone sends electrical impulses to relay neurone in spinal cord
3) Motor neurone sends electrical impulses to effector
4) Effector produces a response (move hand away)
