Nervous System - Nerves 2 Flashcards
What 5 components make up the central nervous system?
CNS can be divided into 5 areas caudal (bottom) to rostral (top) which are -
Spinal cord
Brainstem - medulla oblongata, pons and midbrain
Diencephalon - thalamus, hypothalamus and epithalamus
Cerebellum
Cerebral hemisphere
Describe the anatomy of the spinal cord.
Grey matter;
Consists of nerve cell bodies, dendrites, and unmyelinated axons
Ventral horns - contain motor neurons
Dorsal horns - receive sensory information from PNS and contain interneurons involved in reflex arcs
White matter;
Consists of myelinated axons bundled into tracts
White matter surrounds grey matter
Dorsal columns - contain ascending sensory tracts
Ventral columns - contain descending motor tracts
Spinal nerves;
Mixed nerves that originate from spinal cord forming PNS
Each spinal nerve begins as an anterior motor and posterior sensory nerve root and they unite at the intervertebral foramina
Consists of 31 pairs of spinal nerves
Begins at the base of the medulla oblongata to the vertebral canal surrounded by spinal meninges containing cerebrospinal fluid
Describe the structure of the cerebrum
Cerebral hemispheres divided by the longitudinal cerebral fissure
Cerebral cortex;
Grey matter, neuronal cell bodies
Brain size is limited therefore sulci and gyri create folds allowing a larger cortical surface aiding greater cognitive function
White matter tracts - beneath the cerebral cortex lies white matter, composed of myelinated axons that form nerve fibre tracts
Basal ganglia - deep within cerebrum
Limbic system - located on the inner border of the cerebrum, is a complex network of structures involved in emotions, memory, and behavior
Describe the cerebellum.
Cerebellum - CNS
Located back of the brain immediately inferior to the occipital and temporal lobes
Important role in motor control
Doesn’t initiate movement but contributes to coordination, timing and precision
2 dominant neurones - Purkinje cells and granule cells.
Describe the brainstem.
Midbrain - portion of the CNS associated with vision, hearing, motor control
Pons - relays sensory information to cerebellum and thalamus, somatic and visceral motor centres
Medulla oblongata - autonomic functions of breathing, heart rate and blood pressure.
Describe the diencephalon.
Thalamus - relays sensory information between brain regions and controls autonomic functions of PNS
Hypothalamus - links nervous system to the endocrine system via the pituitary gland
Pineal gland - produces melatonin which modulates sleep patterns.
What are the 4 lobes of the cerebrum and their associated function?
Parietal lobe - processing sensory information.
Temporal lobe - auditory processing
Occipital lobe - vision
Frontal lobe - decision making, emotions
Describe the structure and function of the meninges.
Meninges are the membranous coverings of the brain and spinal cord
The 3 layers are the dura mater, arachnoid mater and pia mater
Functions :
Provide a supportive framework for cerebral and cranial vasculature
With cerebrospinal fluid protect CNS from mechanical damage
Involved in cerebral pathology
Dura mater - dense connective tissue continuous with periosteum of skull
Arachnoid matter - 2 components, layer touching dura mater and a system of trabeculae connecting to pia mater, cavity between trabeculae filled with cerebrospinal fluid
Pia mater - loose connective tissue containing many blood vessels and covered by squamous cells, only covering to follow the contours of the brain .
Describe the choroid plexus.
Collection of cells that produce cerebrospinal fluid in ventricles of the brain
Consists of modified ependymal cells
500ml CSF produced per day
CSF purposes - protection, homeostasis, clearing waste.
What is the posterior and anterior rami?
Posterior rami - supplies nerve fibres to synovial joints of vertebral column, deep muscles of back and overlying skin
Anterior rami - supplies nerve fibres to rest of body
