LP #104 Flashcards
Nervous system 3 main functions
Receives- receptors
Sorts & interprets- control centre
Responds to stimuli-effectors
What are 2 functional mods of the nervous system?
- sensory
- receiving, sorting & interpreting signals
- keeping us apprised of what is happening in the internal & external environments
- motor
- responding to signals
- effecting change
Describe the terms afferent & efferent with respect to the nervous system?
- afferent: to the CNS from the PNS
* efferent: to the PNS from the CNS
What are the 4 structural areas of the brain?
- cerebral hemispheres (cerebrum)
- diencephalon
- cerebellum
- brain stem
What is the physical relationship between the brain and spinal cord?
The SC is the inferior continuation of the brain
How many hemispheres and lobes does the human brain have?
- frontal
- parietal
- temporal
- occipital
What are the names of the folds and ridges on the cerebral cortex?
What is their purpose?
- -sulci (shallow grooves)- sulcus (sing)
- fissures (deep grooves)
- gyri (ridges)- gyrus (sing) - Major fxn:
- increase the functional surface area
- compartmentalize the brain, separating different functional areas
What are the different mapped ‘areas’ of the brain known as?
What are the 3 types of these areas?
- cortical areas are mapped into 52 areas collectively referred to as Brodmann areas
- sensory, association, motor
Are the left and right hemispheres of the brain identical?
Cortices of the two hemispheres are similar but not identical
Name the major sensory (7) of the cerebral cortex
Sensory:
- primary somatosensory cortex
- somatosensory association area
- areas of special senses:
- vision
- hearing
- smell
- taste
- equilibrium
Name the major motor (5) areas of the cerebral cortex
- primary motor area
- premotor cortex
- frontal eye field
- prefrontal cortex
- Broca’s area
What are the 2 primary functional areas of the diencephalon and what are their functions?
- thalamus: sorts sensory input
- hypothalamus: integrates & regulates autonomic
- body temp
- appetite & thirst
- water balance
- circadian rhythms (sleep & wake cycles)
- endocrine fxn
What are the 3 areas of the drain stem, from superior to inferior?
- midbrain
- pons
- medulla oblongata
What is the main function of the cerebellum?
Coordinates:
- smooth movement
- balance
- posture and m tone
The H in the spinal cord cross section is comprised of?
Surrounding the H is myelinated tissue referred to as?
- the SC contains an H-shaped section of grey matter surrounded by white matter known as white columns
- bilateral projections of SC grey matter are the dorsal horns, ventral horns, & lateral horns
Distribution of cortical tissue is represented by a funny looking dude known as?
Homunculi
What are the projections of the H called?
What a re bundles of axons in the CNS known as? In the PNS?
- bundles of axons in the CNS are tracts
* bundles of axon in the PNS are nerves
What kind of tissue are the meninges made of?
3 protective layers of CT cover the brain and spinal cord
What are the 3 layers of meninges, from superficial to deep?
- pia mater (inner layer)
- arachnoid mater (middle layer)
- dura mater (outer layer)
How many cranial and spinal nerves are there?
Are spinal nerves sensory, motor or mixed? Cranial nerves?
*PNS consists of all nerve structures that lie outside the brain & SC: Cranial nerves (12 pairs) Spinal nerves (31 pairs)
- all spinal nn are mixed
- cranial nn can be sensory or motor or mixed
How many connections does a spinal nerve have to the spinal cord?
- name them
- describe them functionally
Spinal nn have 2 connections to the SC:
- Ventral root- contains motor fibers
- Dorsal root- contains sensory fibers
What are the somatic branches off a spinal nerve?
What are the autonomic branches off a spinal nerve called?
Rami: ramus= branches
*somatic branches of mixed spinal nerves are the dorsal & ventral ram (contain both sensory & motor nerve fibres)
*automonic branches of spinal nerves are the rami communicantes (contain sympathetic fibres)
What are the 5 main peripheral nerves to branches off the brachial plexus?
What nerves do the ventral rami of the thoracic spinal nerves generally become?
- radial
- musculocutaneous
- median
- ulnar
- axillary
*ventral rami of thoracic nerves become intercostal/subcostal nerves
What are the 2 main nerves that come off the lumbar plexus?
What is the Lumbosacral trunk?
- femoral
- Obturator
- lumbosacral plexus
- overlap of lumbar & sacral nn at lumbosacral trunk, L5 SC segment
What is the primary nerve that comes off the sacral plexus, and what are its main branches (divisions)?
- sciatic n
- common fibular
- deep fibular
- superficial fibular
- tibial
Which spinal nerve rami contribute fibres to a nerve plexus?
What are the 4 somatic nerve plexuses, and what spinal roots to they receive fibres from?
- contributing to the plexuses are the ventral rami of spinal nerves
- cervical (C1-C4): neck, scalp & shoulder
- brachial (C5-T1): upper limb
- lumbar (L1-L4): lower limb
- sacral (L4-S4): gluteal region & lower limb
List the 12 pairs of cranial nerves.
I. Olfactory- nose (sense of smell)- sensory
II. Optic- eye (sense of vision)- sensory
III. Oculomotor- extrinsic eye mm- motor
IV. Trochlear- extrinsic eye mm- motor
V. Trigeminal- mm of mastication; sensory to face- mixed
VI. Abducens- extrinsic eye mm- motor
VII. Facial- mm of facial expression- mixed
VII. Vestibulocochlear- ear (hearing & balance)- sensory
IX. Glossopharyngeal- tongue & pharynx; salivary glands- mixed
X. Vagus- heart, lungs, abdominal viscera- mixed
XI. Accessory- SCM, trapezius- motor
XII. Hypo gloss all- tongue- motor
Where do each o the cranial nerves originate?
The sensory only cranial nerves originate in the special sense organs. The rest of the nerves originate in numerical order from the brain stem (from top to bottom) CN I: nose CN II: eyes CN IV: ears CNs III, IV: midbrain CNs V, VI, VII: pons CNs IX, X, XI, XII: medulla oblongata
Define dermatome?
An area of skin supplied by sensory fibres from a single dorsal root
How is dermatomal Innervation different from peripheral cutaneous Innervation?
- peripheral cutaneous nerves vs. Nerves supplying a dermatome:
- Innervation of a dermatome arises from a single SC segment
- peripheral nerves may originate from different SC segments
Define myotome
- a group of mms supplied by nerves whose fibres arise primarily from a single ventral nerve root
- the mms perform a common action
How is myotomal Innervation different from peripheral motor Innervation?
- peripheral motor nerves vs. Nerves supplying a myotome:
- Innervation of a myotome arises from a single SC segment
- peripheral nerves typically originate from different SC segments
What are the 2 divisions of the autonomic nervous system?
How do we briefly describe their functions?
- Parasympathetic
- rest & digest
- sympathetic
- fight or flight
What is the difference in the motor units between the somatic and autonomic divisions of the nervous system?
- Somatic motor unit includes one neuron & the skeletal mms cells it innervates
- autonomic motor unit includes 2 neurons in a pathway (pre-ganglionic & post-ganglionic) & the effector
Rami communicantes: are they associated with the sympathetic or parasympathetic division of the ANS?
Sympathetic division
The paravertebral and prevertebral ganglia: are they associated with the sympathetic or parasympathetic division of the ANS?
Sympathetic division
