B3.1: The Nervous System Flashcards
What are the two main parts of the nervous system?
CNS: brain and spinal cord
PNS: neurons to and from CNS
What do sensory neurons do?
Carry impulses from receptors to CNS
What do relay neurons do?
Connect sensory and motor neurons in CNS
What do motor neurons do?
Carry impulses from CNS to effectors
What are examples of effectors?
Muscles/glands
What is a synapse?
Gap between neurons were signals pass via neurotransmitters
What is a reflex arc?
the nerve pathway which follows a reflex action
What is the order of a reflex arc?
Stimulus
Receptor cells
Sensory neurone
Spinal cord
Brain
Spinal cord
Motor neurone
Effector
Response
What is the cerebral cortex responsible for?
Thinking
Memory
Intelligence
What does the medulla control?
Breathing
Heart rate
What does the cerebellum control?
Balance
Coordination
What does the hypothalamus do?
Regulate temperature/homeostasis
What is the nervous system?
The highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body
Give an example of a reflex arc
Drops ruler - stimulus
Eye - receptor
Optic nerve - sensory neuron
Brain - CNS
Catching ruler - response
Muscles contract - effector response
Muscles in hand - motor neuron sends a decision in the form of an impulse
What are the receptor cells of an eye?
Light
What are the receptor cells of a tongue?
Taste
What are the receptor cells of an skin?
Pressure and temperature
What are the receptor cells of a nose?
Smell and taste
What is the stimulus for a eye?
Light
What is the stimulus for a tongue?
Chemical
What is the stimulus for a skin?
Pressure and heat
What is the stimulus for a nose?
Chemical and chemical
What is a nerve pathway called?
Reflex arc
What are the components of the CNS?
Spinal Cord
Brain
What are the components of the PNS?
Nerves - sensory, motor, relay
Sensory Receptor
Something that detects the stimuli
Hand, skin
For each of the senses
What is a synapse
The distance between 2 neurons
What are the effectors n the body?
Muscles, Contract
Glands, adrenaline
How can we identify sensory neurons?
Cell body in the middle in the sensory neuron
Where do impulses travel in sensory and motor neurons?
Sensory impulse starts at receptor cells
Motor impulses will have the effector at the end
What is a stimulus?
Change in the environment
What is the hypothalamus?
Thermoregulatory centre
Thermometer of the body
What is the order of a reflex arc?
Stimulus
Receptor cells
Sensory neurone
Spinal cord
Motor neurone
Effector
Response
What are features of the reflex arc?
Doesn’t go to brain
Much quicker
Involuntary
What is homeostasis?
Maintenance of constant environment in the body
What things need to be maintained constant in the body?
Temperature
Water levels
Stress
Blood sugar levels
How does the body respond when the body is too hot?
Vasodilation
Sweating
Hairs lie flat
How does the body respond when the body is too cold?
Vasoconstriction
Shivering
Goosebumps
Stop sweating
What types of cells are in the retina and what are their functions?
Rods - detects light
Cones - detect colour
Why can people be colourblind?
Receptor cells missing/not working well
What is the function of the cornea?
Protects cornea
Refracts light
What is the function of the pupil?
Allows light to enter the eye
What is the function of the iris?
Alters pupil size by contracting/relaxing
What is the function of the lens?
Focuses light clearly onto the retina
What is the function of the ciliary body?
Alters the lens shape
What is the function of the suspensory ligaments?
Connects ciliary muscle to the lens
What is the function of the optic nerve?
Carries nerve impulses to the brain
What is the function of the retina?
Captures picture your eyes see
What must the ciliary body and suspensory ligs to in order for the lens to get FATTER?
SL: contract
CB: relax
What must the ciliary body and suspensory ligs to in order for the lens to get THINNER?
SL: relax
CB: contract
What is myopia?
Short sightedness
Light rays come together too soon
Lens too strong/eyeball too long
What is hyperopia?
Long sightedness
Light rays come together too late
Lens too weak/eyeball too short
What is a convex lens used for?
Correct hyperopia
converging light rays towards a focal point
What is a concave lens used for?
Myopia
Diverging light rays towards a focal point
What are alternatives for glasses?
Contacts
Laser eye surgery
What does the brain do?
Processes all info collected by receptors about changes in environment (internal and external)
What does the pituitary gland do?
Controls the release of hormones
What does the hypothalamus do?
Small region in the centre
Regulation centre
What does the cerebrum do?
Largest region
Consciousness
Memory
What does the medulla do?
Brains stem attached to spinl cord
Heart rate
Breathing
What does the cerebellum do?
Lower rear
Involuntary movements
Balance
What does the skull do?
Protective layer of bone
What are CT scans used for?
Use x rays to create 3D images of inside the body
Should not be used regularly - radiation causes cancer risk
What are MRI scans used for?
Poweful magnets
Identify brain abnormalities
fMRI produces real time images
What are potential NS damages?
Injury
Disease
Genetic condition
Ingsting a toxic substance
What can damage in the PNS lead to?
Inability to detect pain
Numbness
Loss of coordination
What can damage in the CNS lead to?
Loss of common body systems
Memory loss/processing difficulties
Paralysis
What are some POSSIBLE treatments for brain damage?
Radiotherapy
Chemotherapy
Surgery
Deep brain stimulation - inserting an electrode to stimulate
