Anatomy of the nervous system Flashcards
Give an example a unipolar, bipolar and multipolar neurone.
Unipolar - Primary sensory neurone
Bipolar- specialised sensory neurones found in retina and ear
Multipolar- motor neurones and most neurones in the brain
What is an afferent neurone? Give an example.
Neurones that carry information towards the CNS e.g. primary sensory neurones
What is an efferent neurone? Give an example.
Neurones that carry information away from the CNS e.g. motor neurones.
Describe the anatomical position of the dorsal and ventral root.
The ventral root is anterior to the dorsal root in the vertebral canal.
Compare the speed of conduction in myelinated neurones and unmyelinated neurones.
120m/s compared to <1.5 m/s
Give the 6 functions of astrocytes in the CNS.
- Form a barrier between blood vessels and neuronal system to prevent infection
- supply nutrients
- structural systems
- maintain ionic environment
- repair nervous system by formation of scars
- neurotransmitter uptake
Give the function of oligodendrocytes in the CNS.
Produce and maintain the myelin sheath.
It is shared between numerous axons
Give the three functions of microglia in the CNS.
- Immune cells (phagocytic activity)
- Cytotoxic activity
- Promote repair
What are the neuroglia in the PNS called?
Function
Schwann cells
Spiral wrapping
mune functions
important for regeneration
Basement membrane provides substrate for axon to grow along
Grey matter ? White matter?
Grey- neuronal cell bodies and synapses
White- myelinated axons
What are the four compartments of the CNS called?
Forebrain
Midbrain
Hindbrain
Spinal cord
Which 3 compartments comprise the forebrain?
Cerebral hemispheres
Thalamus
Hypothalamus
Describe the cerebral cortex and the functions of the lobes.
Cerebral corten is highly folded grey matter that is 8-% responsible for cognition and 20% responsible for motor and sensory information.
Parietal lobe- pain, touch and proprioception
Frontal lobe- primary motor cortex
Occiptal lobe- primary visual cortex
Temporal lobe- primary auditory and olfaction cortex
Describe the role of the thalamus.
Relay centre for all senses other than smell.
Its in the centre of the brain
Describe the anatomical position of the hypothalamus and its role.
Inferior to the thalamus and is involved in homeostasis via the autonomic nervous system and the endocrine system.
What is the brainstem comprised of and what is its role?
Hindbrain and midbrain
Connects the cerebral cortex to the spinal cord.
It controls the cardiovascular system and the respiratory system
DAMAGE-> DEATH
What is the hindbrain comprised of and what is its role?
What is its anatomical position?
Cerebellum, Pons and Medulla
Control of complex muscular movement
Posterior to the brainstem
Describe the anatomical position of the spinal cord
Sits within the vertebral canal
Begins at the atlas and ends at L1
Describe the PNS and what it does
Peripheral nerves that can be somatic or autonomic that supply the viscera, blood vessels, muscles, gland and skin.
Descrive a somatic neurone
Looks like normal multipolar neurone
What is the somatosensory system?
The part of the sensory system concerned with the conscious perception of touch, pressure, pain, temperature, position, movement, and vibration, which arise from the muscles, joints, skin, and fascia.
Consist of the axons of the primary SN
Whats the difference between exteroceptive and proprioceptive?
Exteroceptive- the stimuli originated from outside the organism
Proprioceptive- the stimuli is internal
What is the difference between cranial and spinal nerves?
Cranial nerves originate from the brainstem/brain
Spinal nerves originate from the spinal cord, lateral to the spinal ganglion and medial to ramus. They occur where the dorsal and ventral nerves merge.
Describe the segmentation of the spinal cord.
Cervical- 8 Thorax- 12 Lumbar- 5 Sacral- 5 Coccygeal nerve- 1
Where do the dorsal primary ramus supply?
Discuss the extension of vertebral column
Skin over the paravertebral gutter
Errector spinal muscle and facet joints of vertebral column
Where do the ventral primary ramus supply?
How are they pathologically different to the DPR
Give an example
The rest of the body including skin, and musculoskeletal system
Much larger
Intercostal nerves supplying the intercostal muscles
What is a nerve plexus?
Occur where ventral primary ramus merge
Forms nerves with axons coming from multiple spinal nerves
Important in INNERVATION OF LIMBS
Difference between a dermatome and a myotome.
An individual area of skin/muscle group that is innervated by a single spinal nerve.
**ARISE FROM SOMITES
Describe why a cutaneous skin condition occurs as a result of a myocardial infarction
Because the nerve that supplies the skin of the left arm shared a synapse with the nerve of the heart
Describe effects mediated by the sympathetic autonomic nervous system.
Where does it originate
Increased heart rate
Vasoconstriction and constriction of abdominal blood vessels
Inhibition of peristalsis and gastric secretion
Pupil dilation
Hair errection
Thoraci-lumbar spinal cord
Describe effects mediated by the parasympathetic autonomic nervous system.
Where does it originate
Decreased heart rate
No effect on blood vessels, skin or hair (except in sweat glands)
Stimulates peristalsis and gastric secretions
Pupil constriction
Narrow bronchi
Origin: brainstem and sacral spinal cord
Describe the structure of autonomic neurones.
Give an exception
How are abdominal neurones different
Preganglionic neurone( which all enter sympathetic trunk)-> Synapse-> Postganglionic neurone (exit via spinal nerve) -> Effector
Adrenal medulla lacks synapse
Abdominal neurones have a preganglionic neurone that enters a splanchnic nerve directly without synapsing-> prevertebral ganglia -> ACh-> Abdominal
How do parasympathetic autonomic neurones differ from sympathetic ones?
Long preganglionic neurone and short postganglionic neurone
Ganglia close to the effector
What are the glands that secrete a) tears and b) saliva called?
a. lacrimal gland
b. parotid/ submandibular gland
Describe the cranial parasympathetic mechanism of the vagus nerve.
Brainstem -> Vagus nerve ->
lungs (bronchoconstriction)
heart (decreased cardiac output)
abdomen (peristalsis)
Describe the sacral parasympathetic action.
Sacral spinal cord -> exit via pelvic splanchnic nerves -> synapses to pelvic organs:
sexual function
Bladder (urination)
Rectum ( defection)
