Nervous System Flashcards
Labels of the eye
Cornea- very outside of the eye
Lens- middle circle(pupil)
Iris- muscle like flaps over the pupil
Fovea- back lines
Explain a function of the retina
Absorbs light, contains rods and cones, colour vision
2 ways the nervous system controls the action of the eye to enable effective sight
Controls dilation to adapt to different light levels, focus image onto the retina, change direction of Vision
Explain an advantage of eye positioning in sheep
Wide angled peripheral vision, early detection of danger, evasive action
Functions of each part of the eye
Iris- controls how much light enters the eye, controls pupil size
Lens- focused light
Retina- absorbs light, detects colour and movement
Cornea- protection, refraction
Describe the role of the tapetum lucidum
Bounces light back, improving vision in nocturnal animals
State the two parts of the central nervous system
Brain and spinal CORD
Explain the function of the parasympathetic nervous system
Slows heartbeat/relax, constricts pupils, stimulates saliva, contracts bladder
How a nerve impulse is transmitted between neurons
Stimulate action potential, synapse, eels ease of neurotransmitter, nerve ending
Symptoms of listeriosis in ruminants
Loss of appetite, fever, facial paralysis, loss of balance
Eyes of an owl adaptation
Binocular vision, see prey
Photoreceptors in the eye
Rods and cones
Adaptations to help animals see in the dark
Large pupils, more rods, specialised reflective layer at back of the eye
Hormone released when an animal is stressed
Adrenaline
How sense organs cause response to stimuli
Receptors detect stimuli, brain processes message, effector generates response, send impulses to CNS
Vasoconstriction-
Happens when an animal gets cold, blood vessels constrict, less blood to the skin, reduced heat loss
Vasodilation-
Happens when an animal gets hot, blood vessels dilate, increased blood flow, cools down
Two types of neuron
Sensory, motor, relay /interneuron
What is a neuron
information messengers. They use electrical impulses and chemical signals to transmit information between different areas of the brain, and between the brain and the rest of the nervous system.
What is a glial cell
Clean up brain debris
Transports nutrients to neurons
Maintains neurons
Provide supporting functions to nervous system
Parasympathetic-
Rest and digest, restores normal body’s functions, neurotransmitter is acetylcholine(Ach), consticts pupils, slows heartbeat, stimulates gastric juice secretion, contracts bladder
Sympathetic-
Prepares for physical activity, neurotransmitter used noradrenaline (NA), dilates pupils, accelerates heartbeat, relaxes bladder, dilated bronchi, stimulates release of glucose
Reflex arc-
Neutral pathway that controls a reflex, allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain
Neuron cells structure
Dendrite- outer coating to the axon, protects and maintains
Cell body/soma- contains genetic info that controls neuron
Nucleus- encapsulates nucleus
Myelin sheath- receive communications from other neutral cells through their tree like projections
Node of ranvier- connects neuron to target cells
Schwann cells- helps to form myelin sheath, speeds up transmission of nerve impulses
Axon terminals- allows impulses to jump by ‘salaries conduction’
Synapse
The junction between two neurons
