Coordination in humans Flashcards
What is the function of the central nervous system (CNS)?
The CNS (brain and spinal cord) coordinates body responses by processing information from receptors and sending signals to effectors.
What is the correct pathway of a nerve impulse?
Stimulus → Receptor → Sensory Neurone → CNS → Motor Neurone → Effector → Response
What are receptors?
Cells that receive stimulus and convert it into electric impulses. Light, sound, heat and touch receptors
What are effectors?
Tissues that bring up a response. Ex: muscles, glands
What is the role of a sensory neurone?
It transmits electrical impulses from receptors to the CNS.
What is a synapse and how do impulses cross them?
- A synapse is a small gap between two neurones.
- Impulses cross synapses by neurotransmitters.
What is a reflex arc?
A rapid, automatic response to stimuli that bypasses the brain for quicker reaction to protect the body from danger.
What is the function of a relay neurone?
It connects sensory and motor neurones within the CNS to relay impulses.
How do hormones travel in the body?
Hormones are secreted by glands and travel through the bloodstream to target organs.
What is the function of adrenaline?
- It prepares the body for “fight or flight”
- Increases heart rate, breathing rate, and blood glucose levels.
- Dialates pupils for better vision
How does insulin regulate blood glucose levels?
Insulin stimulates the liver to convert excess glucose into glycogen for storage.
How does hormonal coordination differ from nervous coordination?
- Feature |Nervous |Hormonal
- Signal Type|Electrical|Chemical
- Speed |Fast |Slow
- Transport |Neurone|Blood
- Duration |Short |Long-lasting
What is the function of the cornea?
It refracts (bends) light
What is the function of the retina?
It contains light receptors (rods & cones) that convert light into electrical impulses.
What do rods and cones detect?
- Rods: Black & white vision (dim light).
- Cones: Color vision (bright light).
What happens to the pupil in bright light?
The pupil constricts (gets smaller) because circular muscles contract and radial muscles relax.
What happens to the pupil in dim light?
The pupil dilates (gets larger) because circular muscles relax and radial muscles contract.
What happens to the lens when focusing on a distant object?
- Ciliary muscles relax.
- Suspensory ligaments tighten.
- Lens becomes thinner (less convex).
What happens to the lens when focusing on a near object?
- Ciliary muscles contract.
- Suspensory ligaments loosen.
- Lens becomes thicker (more convex).
What is homeostasis?
The regulation of internal conditions to maintain a stable environment.
How does the body respond to overheating?
- Sweating: Sweat evaporates, cooling the body.
- Vasodilation: Blood vessels widen, increasing heat loss.
How does the body respond to overcooling?
- Vasoconstriction: Blood vessels narrow to retain heat.
- Shivering: Muscle contractions generate heat.
- Hairs stand up: Traps air for insulation.
What is the function of the lens?
helps focus light onto the retina.
