Lab 8 Flashcards
Central Nervous System (CNS)
which includes the brain and spinal cord occupying the dorsal body cavity.
Peripheral Nervous System (PNS)
which consists mainly of the nerves which extend from
the brain and spinal cord, the cranial and spinal nerves.
3 basic functions of NS
Sensory
- Sensory receptors detect internal and external stimuli
- sensory information is carried to the brain and spinal cord through cranial and spinal nerves.
Integrative
-The brain and spinal cord process, integrate and coordinate this incoming sensory information to formulate an appropriate response
Motor
-motor response is initiated by activating effector organs (muscles and glands) through cranial and spinal nerves.
CNS 3 main protective structures
- Skull/Vertebral Column: a bony outer covering
- Meninges: three layers of membrane called
- Cerebrospinal fluid: watery fluid
Skull and Vertebral Column
• sutures: immovable joints that join together bone
- All the bones of the adult skull
- except the mandible (lower jaw) & three small bones of the middle ear
•cerebrum is divided up into various regions or lobes
•lobes are named after the bones of the skull which overlie the brain
• Foramina - small holes
• Foramen magnum - large hole at its base
• vertebral column is composed of 33 vertebrae
• Vertebral foramen: each vertebra has a large hole, the vertebral foramen, through which the spinal cord passes.
several small holes in skull through which many of the cranial nerves exit
foramina
large hole at skull base through which the spinal cord passes as it enters the vertebral column
foramen magnum
each vertebra has a large hole through which the spinal cord passes.
vertebral foramen
3 layers of connective tissue in brain
Called meninges (singular: meninx):
- dura mater
- periosteal dura mater
- meningeal dura mater
- arachnoid mater
- pia mater
dura mater
- outermost meninx
- 2 layers: periosteal dura mater, meningeal dura mater
- The dural layers are fused together except where they separate under the cranium to form dural venous sinuses (eg. superior sagittal sinus) that collect venous blood from the brain and transfer it into the internal jugular veins.
- The spinal cord does not have a periosteal dura mater layer.
- epidural space: between the wall of the bony vertebral foramen and the spinal dura mater, filled with fatty tissue for cushioning.
periosteal dura mater,
-closely attached to the inner surface of the bones of the skull
meningeal dura mater
- forms the actual external covering over the brain
- sends one extension down between the cerebrum and cerebellum, and another between the two cerebral hemispheres (FN: anchor the brain inside the cranial cavity)
arachnoid mater
- middle layer of the meninges
- filmy, cobweb like material with spider-like extension
- Beneath the arachnoid mater is a wide separation called the subarachnoid space
pia mater
- innermost meninx
- very delicate
- highly vascularized membrane composed of areolar connective tissue
- adheres closely to the surface contours of the brain and spinal cord and dips deeply into the grooves
- not possible to separate the pia mater from the surface of the brain and spinal cord.
- anchor the spinal cord to the dura mater at regular intervals, limiting sideways movement of the cord.
epidural space
between the wall of the bony vertebral foramen and the spinal dura mater, filled with fatty tissue for cushioning.
subarachnoid space
contains cerebrospinal fluid and also the largest blood vessels serving the brain
between Pia & arannoid
Cerebrospinal Fluid
- watery fluid with a composition similar to blood plasma and interstitial fluid
- fills the four ventricles of the brain and the central canal
- FUNCTION: as a cushion for the entire central nervous system, protecting the soft tissue from jolts and blows
- continuously produced by capillaries in the choroid plexuses found in the roof of each ventricle.
- CFS produced and drained at a constant rate
- in subarachnoid space, CSF is absorbed by the arachnoid villi
CSF continuously produced by capillaries in the ______ found in the roof of each ventricle
choroid plexuses
____ knobby projections of the arachnoid mater, to enter the venous blood in the dural sinuses. CSF is absorbed by this in the subarachnoid space
removes CSF
arachnoid villis
List ventricles and connentions
- lateral ventricles, two large cavities filled with cerebrospinal fluid (numbered one and two)
- third ventricle can be seen as a shallow depression surrounding the thalamus, an oval mass beneath the lateral ventricle
- fourth ventricle, a triangular space between the pons and the cerebellum
- cerebral aqueduct: connects 3 to 4
- corpus callosum: forms an arch above the lateral ventricles
- central canal of the spinal cord: continuous with 4th ventricle
What is hydrocephalus
is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased pressure inside the skull.
A build up of cerebrospinal fluid occurs within the ventricles of the brain
What is meningitis?
is an inflammation (swelling) of the protective membranes covering the brain and spinal cord. A bacterial or viral infection of the fluid surrounding the brain and spinal cord usually causes the swelling.
What’s the largest portion of the brain?
Surface is highly convoluted with?
cerebrum
gyri (singular gyrus) = fold/ridges/elevations
sulci (singular sulcus) = grooves/depressions
fissures = deeper grooves
separates the cerebrum into right and left cerebral hemispheres
longitudinal fissure
a structure composed of nerve fibers which conduct impulses between the two hemispheres of the cerebrum.
corpus callosum
cerebellum
- concerned with the involuntary coordination of skeletal muscle activity and the control of balance and equilibrium.
- outer cortex made up of gray matter
- inner region of white matter
midbrain
is the topmost part of the brainstem, the connection central between the brain and the spinal cord
- four rounded prominences on the dorsal midbrain surface.
- The superior pair are visual reflex centers that coordinate head and eye movements when viewing a moving object.
- The inferior pair are involved in the pathway of sound from the hearing receptors of the ear to the sensory cortex and also turning of the head towards sound in the startle reflex.
corpora quadrigemina
medulla oblongata
contains many vital autonomic centers involved in the control of heart rate, respiratory rate, and blood pressure
pons
pons = bridge
connect parts of the cerebellum and the medulla with the cerebrum.
crossover point for the major motor tract descending from the cerebrum to the spinal cord
pyramids
insula
fifth lobe deep within the lateral sulcus and is not visible unless parts of the other lobes are removed.
precentral gyrus:
contains the primary motor area which is responsible for voluntary movement of skeletal muscle.
postcentral gyrus:
contains the primary sensory area which receives information from sensory receptors for pressure, pain and temperature
thalamus
important relay station for sensory impulses passing upward to the cerebral cortex.
relay station for sensory impulses (hearing, sight, eveything but sence of smell)
Hypothalamus
FUNCTION:
regulate bod temp, control appitite, emotions like fear/rage, stores some hormones that are produced in pituitary gland. Produces hormones to control pituitary gland. Basically the master of the pituitary gland.
involved in many vital processes such as regulating body temperature, water balance, appetite, and emotions such as fear and rage. It also regulates the release of hormones from the pituitary gland.
thalamus + hypothalamus =
diencephalon
The point at which these nerves emerge from the surface of the brain is referred to as their ________the area within the brain where the nerve fibers actually begin is known as their______.
superficial origin
deep origin