Ch.8- Central Nervous System

What does the Central Nervous System consist of?

The brain and spinal cord

What serves a major center for registering sensations, making decisions, and storing memory?

The brain

Composed of bone, surrounds brain

Skull

What are Cranial Meninges

Three layers of membrane surrounding the skull.

What does the Dura Mater- outer layer do?

Forms a protective bag around the brain

What is The Dura Mater-outer layer made of?

dense irregular connective tissue

What is epidural space?

space between the skull and dura mater. composed of adipose and serves a pad

What serves as the middle layer of the meninges?

The arachnoid layer

What makes Arachnoid layer special?

large supply of collagen and elastic fibers. Looks like a spider web (avascular)

What is the Pia Mater

innermost of the three meninges

Characteristics of Pia Mater

transparent connective tissue. Layer is highly vascular. Supplies nutrients and oxygen to brain.

What is subarachnoid space?

Space between the pia mater and the arachnoid layer. Contains cerebrospinal fluid

What is Cerebrospinal fluid

nourishes and protects brain and spinal cord. Circulates through ventricles. (nutrients, waste, protection)

Choroid plexus

net work of capillaries and ependymal cells in the wall of ventricles of the brain that secrete cerebrospinal fluid

Hydrocephalus

disorder in which excess CSF accumulates in the ventricles of the brain. Causes head to bulge and fluid can increase pressure on the brain.

Significance of blood in the brain

huge blood supply. Blood carries oxygen and nutrients to neurons. Loss of oxygen to brain can lead to neuron death within 4 minutes

What are all parts of the brain?

Brain stem, Cerebellum, Diencephalon, and Cerebrum

Brain stem

connects spinal cord to diencephalon. Consist of medulla oblongata, pons, midbrain, and reticular formation

What is medulla oblongata

Forms the inferior portion of the brain stem.

What are parts of the medulla?

Pyramid bulges, cardiovascular center, rhythmicity area

Pyramid bulges

On anterior portion of medulla. Contain tracts that pass from cerebrum to spinal cord

Decussation of Pyramids

region where nerves from pyramids cross over. Neurons on the left side of medulla control effectors on right side of body

Cardiovascular Center

regulates rate and force of heartbeat

Medullary Rhythmicity area

adjusts the rhythm of breathing

Pons

superior to medulla. Serves as a bridge that connects spinal cord and medulla to end of brain

Pneumotaxic/ Apneustic Areas

Can regulate breathing.

Midbrain

extends from pons to diecephalon. Have cerebral aqueduct and Corpora quadrige

Corpora quadrigemina

4 rounded elevations. Superior Colliculi, Inferior Colliculi, Reticular Formation

Reticular Formation

collection of gray matter that has role in waking up or slowing down the cerebrum

What is the Cerebellum?

occupies inferior and posterior aspects of the cranial cavity. Posterior to medulla and pons. Second largest portion of the brain.

What are lobes of the cerebellum referred to as?

Cerebellar Cortex

What are functions of the Cerebellum?

Regulates posture, balance, skilled motor, hand eye coordination

What is the Diencephalon?

begins at the midbrain and extends upwards. Forms walls of third ventricle and consists of thalamus and hypothalamus.

What is the Pineal Gland?

Pea-sized structure located in the diencephalon

What does Pineal Gland do?

function unclear. secretes melatonin which regulates body’s biological clock, and promotes sleepiness

What is the Thalamus

Comprises 80% of the diencephalon

What is intermediate mass

a bridge of gray matter that connects the right and left sides of the thalamus

Functions of Thalamus

serves as a station of impulses from spinal cord to cerebrum, and cognition

Hypothalamus

located inferior to the thalamus

Primary functions of Hypothalamus include:

Regulating homeostasis in the body, Controlling ANS, controlling Pituitary secretions, regulate emotional patterns, regulating hunger and thirst.

What is the hunger center?

produce hunger sensations. Satiety center inhibits hunger sensations once sufficient food supplies ingested

Thirst center

produce thirst sensations

What is Cerebrum?

largest portion of the brain. Divided into two hemispheres

Cerebral Cortex

superficial layer of the cerebrum, composed of gray matter. (contains active neurons and white matter found deep)

Functions of Cerebrum

site of intelligence, allows us to speak, read, and write

Folds and grooves in the brain are called?

gyrus

How is cerebrum separated?

composed of lobes that they are covered by: (frontal lobe, parietal lobe, occipital lobe, temporal lobe)

Corpus Callosum

Band of white matter that connects hemispheres of cerebrum

Motor areas of cerebrum

Primary motor area- produces impulses regulating skeletal muscle contractions, Motor speech are- allow translation of spoken word

Lateralization of function

left hemisphere regulates math and logic, right side controls artistic and music thoughts. (most left dominated are right handed)

What is limbic system?

formed by several structures on innner surface of cerebrum and the diencephalon

what makes um limibic system?

Olfactory bulbs, mammillary bodies,

Olfactory bulbs

flat, rest on cribriform plate. Conduct impulses for smell to cerebrum

functions of limbic system

governing emotions, behavior, memory, and allowing for pleasure, pain, rage, fear, anger, sorrow

Cerebrovascular accident

caused by an interruption of blood supply to the brain. A stroke

Transient Ischemic Attack (TIA)

Temporary episodes of reversible mental disfunction

Alzheimer’s Disease

progressive degeneration of the brain that results in mental deterioration

Brain tumor

any growth within the brain

Dyslexia

impairment of the brain’s ability to translate images received by the eyes into understandable language

Parkinson’s Disease

disorder of the CNS that results in involuntary skeletal muscle contractions that are normally controllable

Huntington’s disease

hereditary disorder that occurs during middle age. Fatal and at present there is no cure

Meningitis

inflammation of the meninges

Concussion

occurs when brain moves within the skull which causes impact damage.

Spinal cord

major connection between brain and body

Vertebral Column

composed of bone tissue. Provides protection to the cord

Spinal Meninges

encircle and protect the spinal cord. Extend from the brain onto the spinal cord

Conus Medullaris

tapered, cone-shaped end of the spinal cord. Near the second lumbar vertebra.

Filum Terminale

an extension of the pia mater; located at the conus medullaris. Attaches the spinal cord to the coccyx.

Cauda Equina

Collection of nerves extending from the conus medullaris of the spinal cord. Nerves extend into the pelvic region and into the legs.

31 pairs of spinal nerves

extend from the spinal cord. Nerves allow for communication between spinal cord and the body. 2 points of attachment on spinal cord from each nerve.

Points of attachment are known as what?

roots. Are posterior root and anterior root.

Gray matter

shaped like a butterfly in the center of the spinal cord.

Gray Commissure

forms the body of the butterfly

Central Canal

small space in the center of the gray commissure. Extends entire length of the spinal cord. Contains cerebrospinal fluid

sides of gray matter are divided into..

horns. posterior and anterior

Where are motor neurons to skeletal muscle located?

anterior horns

Where are motor neurons to cardiac and smooth muscle located?

posterior glands

White matter

surrounds gray matter. Gray matter divides it into 3 major regions known as columns. Anterior, posterior and lateral

Tracts

bundles of nerves associated with the white matter of the right and left sides of spinal cord

Specific functions of spinal cord include

highway for impulse movement. Conducted by white matter.

Integrates and examines incoming and outgoing information/to the brain

Paralysis

loss of motor function

Paraplegia

when individuals lose use of lower limbs

Quadriplegia

when all four limbs are affected. result of damage to cervical position

Hemiplegia

paralysis on one side of body

amyotrophic lateral sclerosis (ALS) (Lou Gehrig Disease)

Descruction of anterior horns of spinal cord. Loss of ability to speak, swallow and breath. No cure

Poliomyelitis

Viral infection marked by fever, headache, stiff neck. Motor neurons could be destroyed.