-
Meninges
membranes located between bone oand soft tissue of nervous system, protect the brain and spinal cord
-
Three layers of meninges
- dura mater
- arachnoid mater
- pia mater
-
dura mater
- outermost layer,
- composed of tough, white, dense connective tissue
- contains many blood vessels and nerves
-
epidural space
- lies between the dural sheath and bony walls
- contains blood vessels, loose connecive tissue and adipose tissue that pad the spinal cord
-
arachnoid mater
- thin, weblike membrane
- lacks blood vessels
- located between the dura and pia maters
-
subarachnoid space
- between the arachnoid and pia maters
- contains cerebrospinal fluid
-
pia mater
- thin and contains many nerves and blood vessels
- nourish the underlying cells of brain and spinal cord
-
ventricles
- located in the cerebral hemispheres and brainstem
- continuous with the central canal of the spinal cord
- filled with csf
-
lateral ventricles
- two
- first in left cerebral hemisphere
- second in right cerebral hemisphere
- extend anteriorly and posteriorly into the cerebral hemispheres
-
third ventricle
located in the midline of the brain beneath the corpus callosum
-
interventricular foramina
- opening at anterior end of third ventricle
- allows communication with lateral ventricles
-
fourth ventricle
- located in the brainstem
- anterior to the cerebellum
- continuous with the central canal of the spinal cord
- has openings in its roof that lead into the subarachnoid space of the meninges.
-
cerebral aqueduct
connects third and fouth ventricle
-
choroid plexuses
- reddish cauliflowerlike masses of specialized capillaries from the pia mater
- secrete csf
-
Route of csf
- csf formed in lateral ventricles
- to intraventricular foramen
- to 3rd ventricle
- to cerbral aquaduct
- to 4th ventricle
- to central canal
- to spinal cord and subarachnoid space
- then to top
-
arachnoid granulations
- tiny fingerlike structures projecting fom subarachnoid space
- reabsorb csf
-
spinal cord
- slender column of nervous tissue continuous with brain and brainsem
- extends downward through vertebral canal
- begins at foramen magnum and terminates at the first and second lumbar vertebrae
-
function of spinal cord
- pathway for nerve impulses to and from brain and brainstem
- center for spinal reflexes
-
filum terminale
- thin cord of connective tissue descending to the upper surface of coccyx
- originates from spinal nerves at lumbar and sacral level
-
cauda equina
- looks like horses tail
- formed from filum terminale and the spinal nerves below the conus medullaris
-
patellar reflex
- also called knee jerk reflex
- uses two nerons - sensory and motor
-
parts of reflex arc
- receptor
- sensory neuron
- interneuron
- motor neuron
- effector
-
receptor
DESCRIPTION - receptor end of a dendrite or a specialized receptor cell in a sensory organ
FUNCTION - sensitive to a specific type of internal or exernal change
-
Sensory neuron
DESCRIPTION - dendrite, cell body, and axon of a sensory neuron
FUNCTION - transmits nerve impulse from the receptor into the brain or spinal cord
-
interneuron
DESCRIPTION - dendrite, cell body, and axon of a neuron within the brain or spinal cord
FUNCTION - serves as processing center; conducts nerve impulse from the sensory neuron to a motor neuron
-
motor neuron
DESCRIPTION - dendrite, cell body, and axon of a motor neuron
FUNCTION - transmits nerve impulse from the brain or spinal cord out to an effector
-
effector
DESCRIPTION - a muscle or gland
FUNCTION - responds to stimulation by the motor neuron and produces the reflex or behavioral action
-
ascending tracts
tracts that conduct sensory impulses to the brain
-
descending tracts
conduct motor impulses from the brain to motor neurons reaching muscles and glands
-
Ascending Tracts
- Fasciculu gracilis and fasciculus cuneatus
- spinothalamic tracts (lateral and anterior)
- spinocerebellar tracts (posterior and anterior
-
descending tracts
- corticospinal tracts (lateral and anterior)
- reticulospinal tracts (lateral, anterior, and medial)
- rubrospinal tracts
-
fasciculus gracilis and fasciculus cuneatus
LOCATION - posterior funiculi
FUNCTION - conduct sensory impulses associated with sense of touch, pressure, and body movement from skin, muscles, tendons and joints to the brain
-
lateral spinothalamic tracts
LOCATION - lateral funiculi
FUNCTION - conduct sensory impulses associated with senses of pain and temperature
-
anterior spinothalamic tracts
LOCATION - anterior fauniculi
FUNCTION - conduct sensory implses associated with senses of touch and pressure
-
apinocerebellar tracts (posterior and anterior)
LOCATION - lateral funiculi
FUNCTION - conduct sensory impulses required for the coordination of muscle movements from muscles of the lower limbs and trunk to the cerbellum
-
corticospinal tracts (lateral and anterior)
LOCATION - laeral and anterior funiculi
FUNCTION- conduct motor impulses associated with voluntary movements from the brain to skeletal muscles
-
reticulospinal tracts (lateral, anterior and medial)
LOCATION - lateral and anterior funiculi
FUNCTION - conduct motor impulses associated with the maintenance of muscle tone and the activity of sweat glands from the brain
-
rubrospinal tracts
LOCATION - lateral funiculi
FUNCTION - conduct motor impulses associated with muscular coordination and the maintenance of posture from the brain
-
brain development
forebrain becomes cerebral hemispheres and diencephalon
midbrain becomes midbrain
hindbrain becoms pons, cerebellum and medulla oblongata
neural tube becomes spinal cord
-
cerebrum
- largest part of the mature brain
- consists of two cerebral hemispheres
-
corpus callosum
- deep bridge of nerve fibers
- connects the cerebral hemispheres
-
gyri
ridges or convolutions separated by grooves
-
sulcus
a shallow to somewhat deep groove
-
fissure
a very deep groove
-
longitudinal fissure
separates the right and left cerebral hemispheres
-
transverse fissure
separates the cerebrum from the cerebellum
-
sulci
divide each hemisphere into lobes
-
frontal lobe
- forms the anterior portion of each cerbral hemisphere.
- bordered posteriorly by a central sulcus
- bordered inferiorly by a lateral sulcus
- FUNCTION - higher intellectual processes for concentrating, planning, complex problem solving, and judging consequences of behavior
- control movements of voluntary skeletal muscles
-
parietal lobe
- posterior to the frontal lobe
- separated from frontal by central sulcus
- FUNCTION: provide sensations of temperature, touch, pressure and pain
- understanding speech and using words to express thoughts and feelings
-
temporal lobe
- inferior to the frontal and parietal lobes and separated from them by the lateral sulcus
- FUNCTION: hearing, remember visual scenes, music, and other complex sensory patterns
-
occipital lobe
- forms the posterior portion of each cerbral hemisphere
- separtated from the cerebellum by the tentorium cerbelli
- FUNCTION: vision
-
tentorium cerebelli
shelflike extension of dura mater
-
Insula
- lobe deep within the lateral sulcus and is covered by parts of the frontal, parietal and temporal lobes
- separated from other lobes by circular sulcus
-
cerebral cortex
- thin layer of gray matter
- the outermost portion of the cereburm
- contains nearly 75% of all the neuron cell bodies in the nervous system
-
-
nuclei
- masses of gray matter deep in cerebral hemispheres
- caudate nucleus, putamen, and globus pallidus
- develop from anterior portion of the forebrain
- produce dopamine
-
diencephalon
- develops from posterior forebrain
- located between the cerebral hemispheres and superior to the brainstem
- surrounds the third ventricle
- largely composed of gray matter
-
thalamus
- located in diancephalon
- bulges into third ventricle
- receives all sensory impulses except for sense of smell and sends them to appropriate part of brain
- relay center
-
hypothalamus
- located in diencephalon
- many nuclei
- inferior to thalamic nuclei
- forms lower walls and floor of the third ventricle
- regulates: heart rate, blood pressure, body temp, water and electrolyte balance, control of hunger and body weight, control of movements and glandular secretions of the stomach and intestines, production of neurosecretory substances to release hormones to regulate growth, control various glands and influence reproductive physiology, sleep and wakefulness
-
optic tracts and optic chiasma
- located in diencephalon
- formed by optic nerve fibers crossing over
-
infundibulum
- located in diencephalon
- conical process behind optic chiasma which the pituitary gland is attached
-
posterior pituitary gland
- hangs from the floor of the hypothalamus
- located in diencephalon
-
mammillary bodies
- located in diencephalon
- two rounded structures behind the infundibulum
-
pineal gland
- located in diencephalon
- forms as a con-shaped evangination from the roof of the diencephalon
-
limbic system
controls emotional experience and expression, can modify the way a person acts, producing feelings such as fear, anger, pleasure and sorrow. Reacts to potentially life threatening upsets in a persons physical or psychological condition.
|
|