Organization of the CNS
- Brain
- Cerebrum (forebrain)
- Diencephalon (thalamus, hypothalamus)
- Cerebellum
- Mesencephalon, Pons, Medulla oblongata (brain stem)
- Spinal cord
Task of the CNS
- Receives continuous flow of information from in and outside of body
- Analyzes and interprets the info
- Synaptic integration
- Sends commands to the body to either:
- Maintain function of vital systems/organs
- Respond to external environment
Meninges and Cerebrospinal Fluid
- Meninges:
- 3 layers surrounding the brain and spinal cord
- Outer meninx = dura mater (thick, supports brain, collects blood and cerebrospinal fluid
from the brain)
- Middle meninx = arachnoid
- Inner meninx = pia mater (tightly attached to neural tissue)
- Cerebrospinal Fluid:
- Formed by capillaries of specialized areas of the pia mater called choroid plexus
- Circulates from the brain's ventricles (open spaces all connected)
- Diffuses from 4th ventricle to the subarachnoid space and circulates around the brain and
the spinal cord
, - Drained into venous sinus through arachnoid villus before entering blood circulation
(relieve pressure)
Cerebrum
- Cerebral cortex
- Responsible for the conscious experience of sensory input
- Site of high nervous association
- Grey matter on top = cell bodies
- Learns and stores information, memory retention & capable of education
- White matter
- Beneath the cortex, composed of myelinated nerve fibers
- Includes:
- Association fibers bw parts of cortex
- Commissural fibers bw the two hemispheres
- Projection fibers: connect cortex to other brain structures and spinal cord
- Basal Nuclei
- Deep within cerebrum close to thalamus
- Paired nuclei composed of large pools of neurons
- Control complex semi-voluntary movements (walking, running)
- Work in conjunction with the cortex and cerebellum
Cerebellum
- Not involved in consciousness and sensation
- Receives information from the inner ear (equilibrium), proprioceptive receptors (muscles, tendons
and joints), And cortex (visual and motor)
- Main role is to prevent distortion of intended movement
- Recieves info regarding status of the body, intended movement, and makes adjustment for a
smooth completion
, - Corrective signals sent via thalamus to the cortex and spinal nuclei
Diencephalon
- Inter brain = hypothalamus, thalamus and epithalamus
- Thalamus = relay station for sensory information, cerebellum and vertebral cortex
- Epithalamus = contains olfactory correlation center and pineal gland (produces melatonin)
- Hypothalamus:
- produces neuropeptides that control anterior pituitary
- Produces neurohormones released by posterior pituitary
- Principal regulator of autonomic nervous system; with the brain stem, *most important
region for control of homeostasis*
Brain Stem
- Govern body function by reflexes
- Large amount of whiet matter
- Mesencephalon
- Visual reflex center: receives visual info controls eye movement
- Auditory reflex secter
- Pons and medulla oblongata
- Contain center for postural reflexes
- Control respiratory movements
- Medulla oblongata is crucial for control of:
- Heart activity
- BP
Cranial Nerves
- 12 pairs
- I (olfactory-shortest) and II (optic) are the only purely sensory nerves and remain in brain
- III-XII all exit from brain stem and innervate structures of the head and neck, sensory and motor
mixed
- Exception is X = Vagus nerve: most widely distributed nerve throughout the body (neck to
abdomen) - carries parasympathetic nervous information
- Brain
- Cerebrum (forebrain)
- Diencephalon (thalamus, hypothalamus)
- Cerebellum
- Mesencephalon, Pons, Medulla oblongata (brain stem)
- Spinal cord
Task of the CNS
- Receives continuous flow of information from in and outside of body
- Analyzes and interprets the info
- Synaptic integration
- Sends commands to the body to either:
- Maintain function of vital systems/organs
- Respond to external environment
Meninges and Cerebrospinal Fluid
- Meninges:
- 3 layers surrounding the brain and spinal cord
- Outer meninx = dura mater (thick, supports brain, collects blood and cerebrospinal fluid
from the brain)
- Middle meninx = arachnoid
- Inner meninx = pia mater (tightly attached to neural tissue)
- Cerebrospinal Fluid:
- Formed by capillaries of specialized areas of the pia mater called choroid plexus
- Circulates from the brain's ventricles (open spaces all connected)
- Diffuses from 4th ventricle to the subarachnoid space and circulates around the brain and
the spinal cord
, - Drained into venous sinus through arachnoid villus before entering blood circulation
(relieve pressure)
Cerebrum
- Cerebral cortex
- Responsible for the conscious experience of sensory input
- Site of high nervous association
- Grey matter on top = cell bodies
- Learns and stores information, memory retention & capable of education
- White matter
- Beneath the cortex, composed of myelinated nerve fibers
- Includes:
- Association fibers bw parts of cortex
- Commissural fibers bw the two hemispheres
- Projection fibers: connect cortex to other brain structures and spinal cord
- Basal Nuclei
- Deep within cerebrum close to thalamus
- Paired nuclei composed of large pools of neurons
- Control complex semi-voluntary movements (walking, running)
- Work in conjunction with the cortex and cerebellum
Cerebellum
- Not involved in consciousness and sensation
- Receives information from the inner ear (equilibrium), proprioceptive receptors (muscles, tendons
and joints), And cortex (visual and motor)
- Main role is to prevent distortion of intended movement
- Recieves info regarding status of the body, intended movement, and makes adjustment for a
smooth completion
, - Corrective signals sent via thalamus to the cortex and spinal nuclei
Diencephalon
- Inter brain = hypothalamus, thalamus and epithalamus
- Thalamus = relay station for sensory information, cerebellum and vertebral cortex
- Epithalamus = contains olfactory correlation center and pineal gland (produces melatonin)
- Hypothalamus:
- produces neuropeptides that control anterior pituitary
- Produces neurohormones released by posterior pituitary
- Principal regulator of autonomic nervous system; with the brain stem, *most important
region for control of homeostasis*
Brain Stem
- Govern body function by reflexes
- Large amount of whiet matter
- Mesencephalon
- Visual reflex center: receives visual info controls eye movement
- Auditory reflex secter
- Pons and medulla oblongata
- Contain center for postural reflexes
- Control respiratory movements
- Medulla oblongata is crucial for control of:
- Heart activity
- BP
Cranial Nerves
- 12 pairs
- I (olfactory-shortest) and II (optic) are the only purely sensory nerves and remain in brain
- III-XII all exit from brain stem and innervate structures of the head and neck, sensory and motor
mixed
- Exception is X = Vagus nerve: most widely distributed nerve throughout the body (neck to
abdomen) - carries parasympathetic nervous information
