The Nervous System

Question 1

what does the central nervous system consist of?

Answer 1

the brain and the spinal cord

Question 2

describe the cerebrum and each hemisphere.

Answer 2

the human brain is dominated by the cerebrum (cerebral cortex). The cerebrum is divided into two cerebral hemispheres which are separated by a median longitudinal fissure.

• right hemisphere is focused on the big picture, left is focused on more detail, very analytical
• each hemisphere is concerned with functions on the opposite side of the body

Question 3

what is the principal function of the frontal lobes?

Answer 3

conscious intellect, judgement and ethics, speech, learned voluntary motor function

Question 4

what is the principal function of the parietal lobes?

Answer 4

recognition and correlation of sensation

Question 5

what is the principal function of the temporal lobes?

Answer 5

hearing and memory

Question 6

what is the principal function of the occipital lobes?

Answer 6

primary visual cortex - receives information from the eyes, association area interprets visual stimuli

Question 7

what is the primary function of the hippocampus?

Answer 7

memory (especially spatial memory)

Question 8

what is the primary function of the corpus callous?

Answer 8

commissural fibres connecting corresponding grey areas of left and right cerebral hemispheres

Question 9

what is the primary function of the broca’s area?

Answer 9

motor speech area which directs muscles of tongue and mouth, usually on the left in right-handed people. - may also be involved in panning speech and other motor activities

Question 10

what is the primary function of the cerebellum?

Answer 10

coordination, balance, posture, learned movements

Question 11

what is the primary function of the thalamus?

Answer 11

relay station, sensory processing (dampens unimportant information) and interpreting

Question 12

what is the primary function of the hypothalamus?

Answer 12

controls homeostasis and autonomic nervous system - regulates thirst, feeding, pituitary hormones, temperature, blood pressure, biological rhythms, dense input from emotional structures such amygdala

• translates these inputs to coordinate physiological (e.g. increase BP) and motivates behavioural responses

Question 13

what is the primary function of the limbic?

Answer 13

group of structures which form emotional/feelings, interacts with cognitive brain

Question 14

what is the primary function of the reticular activating system?

Answer 14

part of reticular formation, “wake up/arousing centre”which stimulate cerebral cortex, filters much sensory inout (e.g. noradrenergic and cholinergic neutrons involved in wakefulness, motivation and attention.

Question 15

name and describe what the brainstem consists of.

Answer 15

midbrain: serves important functions in motor movement, particularly movements of the eye, and in auditory and visual processing
pons: conduction pathway between higher and lower brain centres, respiratory control, emotional behavioural and physiological responses, some visual and auditory reflexes

medulla oblongata: control of HR, BP, RR, vomiting, swallowing, coughing, decussatation of pyramids, conduction pathway between higher brain centres and spinal cord. contains many of the cranial nerves and pre-sympathetic nerves

Question 16

could a stroke affect the brainstem?

Answer 16

can affect vital functions such as breathing, vasomotor control and HR

brainstem controls all basic activities of the central nervous system, consciousness, Bp, and breathing. all of the motor control for the body flows through it. brain stem strokes can impair any or all of these functions.

Question 17

what is the brain protected by?

Answer 17

skull (bone), membranes (meninges), and cerebrospinal fluid (CSF)

Question 18

what are ascending and descending tracts?

Answer 18

ascending - carry info from the body, upwards to the brain

descending - carry info from the brain downwards to initiate and control body functions

Question 19

describe the spinal cord.

Answer 19

lies in the vertebral column from the foramen magnum of the skull to the level of the first of second lumbar verterbra (just inferior to the ribs). Like the brain, the spinal cord is protected by the bone, the meninges and the CSF

Question 20

what is the peripheral nervous system?

Answer 20

connects the body and the central nervous system.
composed of all nervous tide outside of the CNS
- cranial nerves, spinal nerves, ganglia and sensory receptors

Question 21

what is the sensory division of the PNS?

Answer 21

also known as the afferent division = going towards the CNS

sensory receptors respond to changes in the environment including light, temperature changes, pressure, chemicals and pain and send sensory information to the CNS via the dorsal root ganglia, located just outside the spinal cord

Question 22

what is the motor division of the PNS?

Answer 22

also known as the afferent division = going away from the CNS
divided into the somatic NS and autonomic NS

• somatic NS conducts nerve impulses via motor neurons from the CNS to cause contraction of skeletal muscles
• autonomic NS AKA involuntary NS as functions modulated by ANS are not under conscious control. the motor nerve fibres of the ANS regulate the activity of smooth muscles, cardiac muscles and glands

Question 23

compare the somatic and autonomic NS.

Answer 23

somatic - includes both sensory and motor neurone. sensory neutrons are related to touch, pain, temp, sight, hearing, taste, smell and equilibrium. motor neurons innervate skeletal muscles.

autonomic - receives input from sensory receptors located in organs, blood vessels, muscles and the NS

Question 24

what is the parasympathetic division?

Answer 24

FEED AND READ.

protective and concerned with rest, digestion, elimination and reproductive function (maintenance of the body)

Question 25

what is the sympathetic division?

Answer 25

FIGHT OR FLIGHT.
stimulation/activation leads to increased alertness and metabolism to be ready for an emergency and also in situations of increased physical activity

• during sympathetic activity, nonessential activities are decreased
• several medical conditions such as haemorrhage, septic shock and anaphylactic shock stipulate sympathetic NS activity