Nervous System pt.2

brain and spinal cord

Central nervous system (CNS)

All the nervous tissue outside the CNS

Peripheral nervous system (PNS)

Extends from the foramen magnum to the 2nd lumbar vertebra

Spinal Cord

• center of spinal cord

• looks like letter H or a butterfly

GRAY MATTER

• Outer layer of spinal cord

• contains myelinated fibers

WHITE MATTER

contain axons which synapse with interneurons

Posterior horns

contain somatic neurons

Anterior horns

contain autonomic neurons

Lateral horns

fluid filled space in center of cord

Central canal

Occurs when muscles contract in response to a stretching force applied to them; simplest reflex

STRETCH REFLEX

to remove a limb or another body part from a painful stimulus

WITHDRAWAL REFLEX

• Spinal nerves C1-4

• Innervates muscles attached to hyoid bone and skin of neck and back of head.

CERVICAL PLEXUS

innervates the diaphragm

phrenic nerve

• Originates from spinal nerves C5-T1

• Supply nerves to the upper limbs, shoulders, hand.

BRACHIAL PLEXUS

• Originates from spinal nerves L1 to S4

• Supplies nerves lower limbs

LUMBOSACRAL PLEXUS

The area of skin supplied with sensory innervation by a pair of spinal nerves.

Dermatome

• the brainstem • the cerebellum • the diencephalon • the cerebrum

The four major regions of the brain are

• regulates heart rate, blood vessel diameter, breathing, swallowing, vomiting, hiccupping, coughing, sneezing, balance

Medulla oblongata

• breathing, chewing, salivation, swallowing • relay station between cerebrum and cerebellum

Pons

• coordinated eye movement, pupil diameter, turning head toward noise

Midbrain

• means “little brain” • cortex is composed of gyri, sulci, gray matter

Cerebellum

Located between the brainstem and cerebrum

Diencephalon

• influences moods and detects pain

Thalamus

• emotional and visceral response to odors; contains the pineal gland

Epithalamus

• controls homeostasis, body temp, thirst, hunger, fear, rage, sexual emotions

Hypothalamus

Largest portion of brain

Cerebrum

divides cerebrum into left and right hemispheres

Longitudinal fissure

folds on cerebral cortex that increase surface area

Gyri

shallow indentations

Sulci

• controls thinking, communicating

• remembering, understanding, and initiates voluntary movements

Cerebral Cortex

• controls LEFT side of body • responsible for music, art, abstract ideas

Right hemisphere

• controls RIGHT side of body • responsible for math, analytic, and speech

Left hemisphere

connection between the two hemispheres

Corpus callosum

• controls voluntary motor functions, aggression, moods, smell

FRONTAL LOBE

• evaluates sensory input such as touch, pain, pressure, temperature, taste

PARIETAL LOBE

• vision

OCCIPITAL LOBE

• hearing, smell, memory

TEMPORAL LOBE

Pain, temperature, light touch, pressure, tickle, and itch sensations

Spinothalamic

Proprioception, touch, deep pressure, and vibration

Dorsal column

Proprioception to cerebellum

Spinocerebellar (anterior and posterior)

general sensory area

PRIMARY SOMATOSENSORY CORTEX

Somatic motor neurons innervate skeletal muscles.

• maintaining the body’s posture and balance

• moving the trunk, head, limbs, tongue, and eyes

• communicating through facial expressions and speech

Somatic Motor Functions

• control voluntary motor movement

PRIMARY MOTOR CORTEX

• where motor functions are organized before initiation

PREMOTOR AREA

• motivation and foresight to plan and initiate movement

PREFRONTAL AREA

Corticospinal tracts are considered /////

DIRECT

• Group of functionally related nuclei • Plan, organize, coordinate motor movements and posture

Basal Nuclei

///// -absent or defective speech or language comprehension

aphasia

• Mainly in left hemisphere

Speech

• parietal lobe • where words are heard and comprehended

Sensory speech (Wernicke’s area)

• frontal lobe • where words are formulated

Motor speech (Broca’s area)

• Electrodes are placed on scalp to record brain’s electrical activity.

Electroencephalogram (EEG)

• person is awake in quiet state

Alpha waves

• intense mental activity

Beta waves

///// -usually observed in children, but they can also occur in adults who are experiencing frustration or who have certain brain disorders

Theta waves

///// -occur during deep sleep, in infants, and in patients with severe brain disorders

Delta waves

///// - task-associated memory; information is retained for a few seconds or minute; bits of info (usually 7)

Working memory

///// -few minutes to a few days; susceptible to brain trauma, drugs

Short-term memory

///// -can last for a few minutes or permanently; length of time memory is stored may depend on how often it is retrieved and used

Long-term memory

///// - retention of facts, such as names, dates, and places, as well as related emotional undertones

Declarative/explicit memory

///// -development of motor skills

Procedural memory/reflexive memory

///// -tough, skin-like outermost covering; thickest layer

DURA MATER

///// -deep to the dura mater and is a much thinner layer and appears spidery

Arachnoid mater

///// -thin, vascular membrane adhering to the surface of the brain

Pia mater

///// - each cerebral hemisphere contains a relatively large cavity

lateral ventricle

///// - a smaller, midline cavity located in the center of the diencephalon between the two halves of the thalamus and connected by foramina (holes) to the lateral ventricles

third ventricle

located at the base of the cerebellum and connected to the third ventricle by a narrow canal, called the cerebral aqueduct

fourth ventricle

12 pair of /////

cranial nerves