🧠 The Nervous System Flashcards
(10 cards)
What are the two parts of the nervous system and their functions?
CNS (brain + spinal cord) processes information; PNS carries impulses between receptors/effectors and the CNS.
Describe the structure and roles of sensory, relay, and motor neurones.
Sensory: from receptors to CNS; Relay: within CNS; Motor: from CNS to effectors (muscles/glands).
What is a reflex and what pathway does it follow?
A fast, automatic response via:
receptor → sensory neurone → relay neurone → motor neurone → effector.
How do synapses transmit signals between neurones?
Chemical neurotransmitters diffuse across the synapse, triggering an impulse in the next neurone.
What are the main parts of the brain and their functions?
• Cerebrum: thought, memory, consciousness
• Cerebellum: coordination, balance
• Medulla: involuntary actions
• Hypothalamus: body temperature, links to endocrine system
• Pituitary gland: releases hormones to control other glands
How is brain function studied and what are the challenges?
MRI scans, electrical stimulation, and case studies. Challenges: ethical issues (e.g. consent), brain’s poor ability to repair.
How does the eye focus on near and distant objects?
• Near: Ciliary muscles contract, suspensory ligaments loosen, lens thickens.
• Distant: Ciliary muscles relax, suspensory ligaments tighten, lens thins.
(Antagonistic muscles)
What are the roles of the cornea, iris, and retina?
Cornea bends light, iris controls pupil size, retina detects light with receptor cells.
What causes short- and long-sightedness and how are they corrected?
• Myopia: image in front of retina, fixed with concave lens.
• Hyperopia: image behind retina, fixed with convex lens.
Why are reflexes quicker than normal responses?
They bypass the brain, using the spinal cord, allowing for faster protective reactions.
