UNIT 4: Central Nervous System Flashcards
What is the central nervous system (CNS)?
The complex of nerves and tissues that control the body’s activities
The CNS is divided into what 2 parts?
Brain and Spinal Cord
The brain: Cortex
outer portion of gray matter
The brain: White matter
inner layer
Parts of the brain
► Cortex: outer portion of gray matter
► White matter: inner layer
► Cerebrum (forebrain)
► Cerebellum (hindbrain)
► Brain stem
- Midbrain
- Pons
- Medulla oblongata
Cerebrum
► Largest part of the brain
► Also known as the forebrain
► Sulci and grooves divide it into lobes and lobules
► Longitudinal sulcus: deep cleft that divides the cerebrum into right and left hemispheres
► Corpus callosum: large commissure between the hemispheres for passage of nerve signals
► Ventricles: cavities in the center of the cerebrum responsible for production, transport, and storage of CSF
What divides the cerebrum into lobes and lobules
Sulci and grooves
deep cleft that divides the cerebrum into right and left hemispheres
Longitudinal sulcus
In the Cerebrum, the large commissure between the hemispheres for passage of nerve signals is the
Corpus callosum
cavities in the center of the cerebrum responsible for production, transport, and storage of CSF
Ventricles
Cerebellum
► Largest part of the hindbrain
► Vermis: area where two hemispheres join together
► Surface contains sulci that give it a cauliflower appearance
► Folia: tissues between the sulci
area of the cerebellum where two hemispheres join together
Vermis
tissues between the sulci in the cerebellum
Folia
Brainstem
► Midbrain: most superior aspect of brainstem
► Pons: bridge between the cerebrum, cerebellum, and medulla oblongata
► Medulla oblongata: bridge between the brain and the spinal cord
most superior aspect of brainstem
Midbrain
bridge between the cerebrum, cerebellum, and medulla oblongata
Pons
Bridge between the brain and the spinal cord
Medulla Oblangota
Ventricular system: 4 ventricles
►4 irregular, fluid-filled cavities that communicate with one another through connecting channels
- Right lateral ventricle
- Left lateral ventricle
- 3rd ventricle
- 4th Ventricle
Ventricular System
► Lateral Ventricles (right and left)
-U shaped
-Body, anterior, posterior, and inferior horns
► Foramen of Monro (interventricular foramen) connects lateral ventricles to the third ventricle
► Third ventricle sits in the midsagittal plane just beneath the lateral ventricles
► Cerebral aqueduct (Aqueduct of Sylvius) connects third and fourth ventricles
► Fourth ventricle
-Diamond shaped
-Located in the hindbrain
-CSF exits the fourth ventricle into the subarachnoid space via the median aperture (foramen of Magendie) and the lateral apertures (foramen of Luschka)
Lateral Ventricles (right and left)
-U shaped
-Body, anterior, posterior, and inferior horns
Foramen of Monro (interventricular foramen)
-connects lateral ventricles to the third ventricle
-communicates with the 3rd ventricle directly, and indirectly with the opposite lateral ventricle
Third ventricle
sits in the midsagittal plane just beneath the lateral ventricles
Cerebral aqueduct (Aqueduct of Sylvius)
connects third and fourth ventricles
Fourth ventricle
► Diamond shaped
► Located in the hindbrain
► CSF exits the fourth ventricle into the subarachnoid space via the median aperture (foramen of Magendie) and the lateral apertures (foramen of Luschka)
Spinal Cord
- Cord extends from the medulla oblongata at the foramen magnum to L1-L2
- Conus Medullaris: cone shaped pointed tail end
- Adult cord is 18 to 20 inches long
- 31 spinal nerves
- Nerves transmitted through the intervertebral and sacral foramina
- Cauda Equina: spinal nerves below the termination of the spinal cord
- Spinal cord and nerves transmit and receive sensory, motor, and reflex messages to and from the brain
cone shaped pointed tail end of spinal cord
Conus Medullaris
spinal nerves below the termination of the spinal cord
Cauda Equina
Meninges: the 3 protective meningeal layers protect the brain and spinal cord
► Pia mater: inner sheath, closely adherent to the underlying brain and cord structure
► Arachnoid layer: middle layer
-Subarachnoid space: continuous with the ventricles
-Contain the CSF
► Dura mater: outer layer composed of two layers
-Subdural space: space between the dura mater and the arachnoid layer
-Epidural space: space between the dura mater and the vertebral periosteum
What are the 3 protective meningeal layers protect the brain and spinal cord
-Pia mater
-Arachnoid layer
-Dura mater
Meninges: Tentorium Cerebelli
tent-shaped fold of dura mater that separates the cerebrum and the cerebellum
Meninges: Dural sac
Dura mater that extends below the spinal cord is the dural sac and it encloses the cauda equina
Falx cerebri
layer of dura that runs through interhemispheric fissure and provides support to cerebral hemispheres
What is the master endocrine gland of the body
Pituitary gland
Filum terminale
Delicate fibrous strand that extends from the terminal tip and attaches the cord to the upper coccygeal segment
What is CSF?
Cerebral Spinal Fluid, tissue fluid of the brain and spinal cord
The midbrain connects the cerebrum to the _______ and _______
Pons, Cerebellum
CSF exits the fourth ventricle into the subarachnoid space via the ____________________________ and the ___________________________
-median aperture (foramen of Magendie)
-lateral apertures (foramen of Luschka)
Spinal cord extends from the __________________ at the foramen magnum to ____-____
Medulla oblongata, L1-L2
Adult spinal cord is ___ to ___ inches long
18-20
How many spinal nerves are on the spinal cord
31
