Structure of the nervous system Flashcards
Review of the arrangement of the nervous system and their characteristics
What are the two parts of the CNS?
The brain and spine
What are the three parts of the brain?
Forebrain, cerebellum, and brainstem
What are the four lobes of the cerebrum?
Frontal, parietal, occipital, temporal
What is the frontal lobe for?
Motor areas, including speech; decision making; higher functions
What is the parietal lobe for?
Integrating visual and sensory information from different sense to build a coherent picture of the world; allows coordination of movements in a complex environment
What is the temporal lobe for?
Memory; face recognition; object recognition; understanding language
What is the occipital lobe for?
Vision; all input from eyes goes here
What are the two layers of the cerebrum?
Grey matter and white matter
What is the grey matter of the cerebral cortex?
Outer layer of the cerebral cortex; composed of cell bodies
What is white matter of the cerebral cortex?
Inner layer of the cerebral cortex; composed of myelinated fibre tracts; carries information in and out of cerebrum
What is the corpus callosum?
Thick bundle of nerves which connects the two hemispheres
What are the protrusions and folds of the cerebral cortex called?
Protrusions are gyrus, folds inwards are sulcus; they increase the surface area of the cortex
What is the function of the basal ganglia?
Are important integrating centres controlling movement, posture, and personality traits
What are the two parts of the forebrain?
Cerebrum and diencephalon
What are the three parts of the diencephalon?
Thalamus, hypothalamus, pituitary gland
What is the function of the thalamus?
Synaptic relay station for all sensory pathways but smell en route to cortex; important integrating centre for inputs to cortex; participates in control of skeletal muscle coordination; key role in awareness
What is the function of the hypothalamus?
Command centre for neural and endocrine coordination; responsible for internal homeostasis; regulate survival behaviours; generates and regulates circadian rhythms; participates in generation of emotional behaviour and regulation of autonomic function; regulated pituitary gland
What is the function of the pituitary gland?
Produces own hormones and stimulates all other hormones-producing glands
What is the limbic system?
Set of structures associated with learning and emotion, coordinated by hypothalamus; frontal lobe, temporal lobe, thalamus, hypothalamus
What are the inputs of the cerebellum?
From muscles and joints, skin, eyes and ears, viscera, and motor cortex
What are the roles of the cerebellum?
Coordination of movements (posture and balance), participates in skill learning
What is the brainstem?
Contains all fibres passing between spinal cord, forebrain, and cerebellum
What are the three parts of the brainstem?
Midbrain, pons, and medulla
What runs through the brainstem?
Reticular formation
What is the function of the reticular formation?
Connects spinal cord to forebrain and cerebellum; receives and integrates input from all regions of CNS; innervates most regions of brain and spinal cord (arousal, wakefulness, attention); is the only part of the brain essential for life
What are the roles of the brainstem?
Motor function, CV control, respiratory control, sleep, wakefulness, attention
How many pairs of spinal nerves are there?
31 pairs
What is the grey matter of the spinal cord?
Entering axons of afferent neurons, interneurons, cell bodies and dendrites of efferent neurons, and glial cells
What is the white matter of the spinal cord?
Myelinated axons; bidirectional transfer of information
What is the dorsal root?
Where afferent nerve fibres enter spinal cord
What is the dorsal root ganglion?
Contains cell bodies of afferent neurons
What is the ventral root?
Where axons of efferent neurons leave cord
What are spinal nerves?
Dorsal and ventral roots from same level of spinal cord combine; have one on each side of the body
What do cervical nerves do?
Control muscles and glands; receive sensory information from neck, shoulder, arms and hands
What do thoracic nerves innervate?
Chest and abdominal walls
What do lumbar nerves innervate?
Hips and legs
What do sacral nerves innervate?
Genitals and lower gastrointestinal tract
How many cranial nerves are there?
12 pairs
How many nerves are there total?
43 pairs of nerves
How are cranial nerves named?
For organ they innervate, and roman numerals for order they appear on inferior surface of the brain
Name a nerve which is exclusively afferent?
Optic nerve
What are the two divisions of the PNS?
Afferent and efferent
What is the afferent division of the PNS?
Sensory receptors to CNS; long part of axon outside CNS
What is the efferent division of the PNS?
CNS to the muscles and glands
What are the two divisions of the efferent PNS?
Somatic and autonomic
What is the somatic PNS?
To skeletal muscles, is only excitatory
What is the neurotransmitter of the SPNS?
Ach, binds to nicotinic receptors
How many neurons are in a somatic pathway?
A singular neuron to the effector muscle
Where is the cell body of a somatic neuron located?
Within CNS (brainstem or spinal cord)
What is the structure of a somatic neuron?
Large diameter, and myelinated, so action potential is rapidly conducted
How many neurons is involved in the automatic pathway?
Two neurons connect CNS to effector cells to smooth/cardiac/GI neurons; have autonomic ganglion/synapse in PNS
What are the two sections of the autonomic PNS?
Parasympathetic and sympathetic
Which branch of the autonomic PNS is involved in rest and digest?
Parasympathetic
Which branch of the autonomic PNS has ganglia close to target organ?
Parasympathetic
Where do the nerves of the parasympathetic system leave the CNS?
At the level of the brain and sacral spine
Where do the nerves of the sympathetic system leave the CNS?
At the level of the thoracic and lumbar spine
What is the neurotransmitter of the parasympathetic pathway?
ACh acts as NT, binding with nicotinic receptors
What are collateral ganglia?
A second abdominal cavity ganglia nearer to effector organ in sympathetic pathway
Where is primary ganglia within the sympathetic pathway?
Close to spinal cord
What is the neurotransmitter of the sympathetic pathway?
ACh acts as NT for first synapse, NE and Epi act as NT for second synapse; NE an Epi bind to adrenergic receptors
What are sympathetic trunks?
On each side of spinal cord, extend length of cord; preganglionic sympathetic neurons which leave cord between T1 and L2 and travel up and down trunk before synapsing; alternative pathways, e.g. collateral ganglia; SNS can act as a single unit, whilst PSNS is made up of independent components; responses are tailored to specific demands
