Module 9: CNS & Nervous Tissue Flashcards
Name the two systems that maintain homeostasis & how
Nervous by nerve impulses & Endocrine by hormones
Describe the path of a neural signal during muscle movement
- sensory neurons detect a stimulus
- sends info to CNS
- interneurons determines movement & sends response to motor neuron
- motor neuron sends message muscle to move
Name the two branches of the nervous system
Peripheral & Central nervous system
CNS includes what?
brain & spinal cord
Peripheral Nervous System: name function & contains
governs rest of body; contains Cranial & Spinal Nerves
Sensory Nervous System
of the PNS; carries sensation to CNS (brain & spinal cord)
Motor Nervous System
of the PNS; carries information from the brain & spinal cord to the rest of the body
Name two subdivisions of the PNS
Sensory NS & Motor NS
Name the subdivisions of the Motor Nervous System
Somatic & Visceral divisions
Somatic Nervous System
carries info to skeletal muscles; controls voluntary movements
Visceral Nervous System
aka Autonomic NS; Autonomous - carries info to smooth muscle (cardiac muscle & glands)
Autonomous as refers to heart
heart is beating but you do not control beating of heart
Name subdivisions of Visceral Nervous System
Sympathetic & Parasympathetic Nervous system
Sympathetic NS
works during stress producing “flight or flight” response
Parasympathetic NS
maintains regular fxn of body, regulating resting & digesting fxns
Function of the Spinal Cord
Conduction, Locomotion, Reflexes
Spinal cord contains bundles of nerve fibers called what?
Tracts
Function of Tracts
carry information up or down the cord (aka conduction)
Locomotion
groups of neurons that control output to the flexor & extensor muscles that allow alternating movements of limbs
Reflexes
regulating automatic involuntary responses for posture, movement & protection
Spinal cord is divided into four regions, name them
Cervical, Thoracic, Lumbar, Sacral
The cervical enlargement contains what?
contains start of nerve branches that go to upper limbs (arms); C5-C7
The Lumbar enlargement contains what?
start of nerve branches that go to lower limbs (pelvis & legs); L1-L2
Cauda Equina - describe
horse tail-like; bundle of spinal nerves that arise from medullary cone & innervates the lower limbs
Cauda Equina - contains..
lumbar nerves 2-5, all sacral nerves & coccygeal nerves
How many pairs of spinal nerves in the spinal cord
31 pairs
Describe structure of spinal cord: start to end
- continuous with brain stem
- housed within vertebral foramina
- starts at opening at foramen magnum in occipital bone
- ends at tapered region near first lumbar vertebra called medullary cone
Meninges
- Surround spinal cord
- protective fibrous coverings of brain & spinal cord.
- Consists of three layers: Dura Mater, Arachnoid Mater, Pia Mater
Dura Mater
outer layer, contains collagen & provides physical protection for brain & spinal cord
Arachnoid Mater
- middle layer
- consists of loosely organized collagen & elastin fibers.
- contains subarachnoid space
Subarachnoid Space
- gaps between the arachnoid mater & pia mater
- space contains cerebrospinal fluid (CSF)
Pia Mater
Inner layer, delicate & contains highly vascular membrane that directly contacts surface of CNS
Name the two types of spinal cord nervous tissue
White & Grey Matter
Gray Matter
- forms H butterfly shape and is central tissue of spinal cord consists of unmyelinated tissue
- contains synapses of spinal cord (such as somas, dendrites & distal ends of axons)
- surrounds central canal
Central Canal
hollow tube that runs the length of spinal cord & contains CSF
White Matter
- outer tissue of spinal cord, consists of myelinated bundles called tracts
Tracts
Ascending & Descending; carry sensory & motor information
Ascending Tracts
carry sensory information from peripheral tissues to brain
Descending Tracts
carry motor information from the brain down to effectors such as muscles or glands
Spinal Nerves
- bundles of myelinated axons
- containing sensory & motor axons
Each spinal nerve is connected to the spinal cord by two roots, name them…
Anterior Root (contains motor axons) & Posterior Root (contains sensory axons)
Posterior root has an area outside of the CNS where there are clusters of Somas called….
Posterior Root Ganglion
There are 31 pairs of spinal nerves, name them
8 Cervical (C1-C8) 12 Thoracic (T1-T12) 5 Lumbar (L1-L5) 5 Sacral (S1-S5) 1 Coccygeal
Brain contains 4 internal chambers called…
Ventricles
Ventricles
Major site of CSF Production
Cerebrospinal Fluid (CSF) - Description & location
- clear fluid that is derived from plasma
- found in ventricles, central canal, subarachnoid space of meninges
Cerebrospinal Fluid (CSF) - Functions
- buoyancy so brain can stay suspended
- protects brain from bumping into skull
- provides chemical stability by removing wastes from CNS
Name four main regions of brain is divided into
Brain stem, cerebellum, diencephalon, cerebrum
Brain Stem
- lowest portion of brain, continuous with spinal cord
- contains Mid-Brain, Pons, Medulla Oblongata
