Ch. 12 Central Nervous System

Sulci

shallow grooves that separate gyri of the brain

Gyri

elevated ridges of the brain

The central sulcus separates which lobes?

frontal and parietal

The parieto-occipital sulcus separates which lobes?

parietal and occipital

The lateral sulcus separates which lobes?

Separates temporal lobe from parietal and frontal lobes

cerebrospinal fluid (CSF)

Fluid produced in the ventricles of the brain that flows in the subarachnoid space and bathes the meninges. Is used to carry dissolved gases, nutrients, and wastes

cerebrospinal fluid is produced where

choroid plexus

Three membranes that protect the brain, superficial to deep

Dura Mater, Arachnoid Mater, Pia Mater

Dura mater

thickest, outermost layer of the meninges surrounding and protecting the brain and spinal cord

arachnoid mater

weblike middle layer of the three meninges

pia mater

thin, delicate inner membrane of the meninges

Blood Brain Barrier

a filtering mechanism of the capillaries that carry blood to the brain and spinal cord tissue, blocking the passage of certain substances.

Cerebrum

Largest part of brain

Controls higher mental functions

Divided into left and right cerebral hemispheres

lateralization of brain function

the unequal representation of various functions in the two hemispheres of the brain

5 lobes of the cerebrum

frontal, parietal, temporal, occipital, insula (deep)

frontal lobe function

involved in motor function: problem solving, memory, judgment, impulse control

parietal lobe function

somatic sensory processing

occipital lobe

A region of the cerebral cortex that processes visual information

temporal lobe

A region of the cerebral cortex responsible for hearing and language.

prefrontal cortex (PFC)

Large frontal-lobe area anterior to the motor and premotor cortex, plays a key role in controlling executive functions such as planning and coordinating

Diencephalon

contains the thalamus, hypothalamus, and epithalamus

thalamus

The brain's relay station (Gateway to the cerebral cortex) for information coming into the cerebral cortex. Afferent information from all senses converges and is sorted and edited. Crude pleasant/unpleasant determination.

hypothalamus

Main visceral control and homeostasis. Autonomic control center that directs blood pressure, rate and force of heart beat, digestive motility and pupil size by controlling smooth and cardiac muscle and glands. It is the center for emotional response, determines pleasure, fear and rage, as well as sex drive. Maintains homeostasis of body temperature, nutrients by controlling appetite and food intake, salt and water balance through control of ADH as well as the sleep wake cycle by directing melatonin release

pituitary gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands. Acts as the major interface between the endocrine and nervous systems.

The brain stem

Connects the brain to spinal cord. Filters information flow between the peripheral nervous system and the rest of the brain.

Regions of the brain stem

midbrain, pons, medulla oblongata

Midbrain

Superior to the pons: integrates sensory information and relays it upward. Also known as the mesencephalon.

Pons

Acts as a relay for conversations between the motor cortex and cerebellum. Helps the medulla maintain breathing rhythm by governing the rate and depth of respirations.

medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion. Relays proprioception information (state of stretch of muscles and joints) to the cerebellum. Controls the cardiovascular and respiratory centers and controls various reflexes such as coughing, vomiting, hiccups, swallowing

Cerebellum

the "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance (smoothes out movements)

ventricles of the brain

Spaces/Canals in the brain that contain and circulate cerebrospinal fluid.

number of ventricles in the brain

4

1st and 2nd ventricles (lateral)

one located in each hemisphere of the cerebrum

3rd ventricle of brain

Ventricle of the diencephalon

4th ventricle of brain

Extends into medulla oblongata

grey matter (makes up cerebral cortex)

Gray matter, named for its pinkish-gray color, is home to neural cell bodies, axon terminals, and dendrites, as well as all nerve synapses. This brain tissue is abundant in the cerebellum, cerebrum, and brain stem. It also forms a butterfly-shaped portion of the central spinal cord.

white matter

The white matter of your brain and spinal cord is composed of bundles of axons. These axons are coated with myelin, which helps conduct nerve signals and protect the axons.

number of spinal nerves

31 pairs

8 cervical

12 thoracic

5 lumbar

5 sacral

1 coccygeal

regions of the spinal cord

cervical, thoracic, lumbar, sacral

cervical enlargement of spinal cord

Responsible for supplying nerves to the upper limb

C4-T1

Lumbar enlargement of spinal cord

Responsible for supplying nerves to the lower limb

T9-T12

conus medullaris

tapered end of the spinal cord (L1-L2)

filum terminale

fibrous extension of the pia mater; anchors the spinal cord to the coccyx

cauda equina

"horse's tail", a fan of nerve fibers below the spinal cord

dorsal root

the sensory branch of each spinal nerve, contains axons of sensory neurons

ventral root

the motor branch of each spinal nerve, contains axons of motor neurons

dorsal root ganglia

contain cell bodies of sensory neurons in the spinal cord

corpus callosum

A thick band of axons that connects the two cerebral hemispheres and acts as a communication link between them.

pineal gland (epithalamus)

secretes melatonin and is important for circadian rhythm

choroid plexus

A structure found within each of the brain ventricles. The location where CSF is produced by ependymal cells

subdural space

space between dura mater and arachnoid mater

subarachnoid space

a space in the meninges beneath the arachnoid membrane and above the pia mater that contains the cerebrospinal fluid

cerebral aquaduct

connects the third and fourth ventricles

septum pellucidum

separates the lateral ventricles of the cerebral hemispheres

Pathway of CSF through the ventricles

lateral ventricle, inter ventricular foramen, third ventricle, cerebral aqueduct, fourth ventricle, central canal

transverse cerebral fissure

separates cerebrum and cerebellum

precentral gyrus (primary motor cortex)

the strip of frontal cortex, just in front of the central sulcus, that is crucial for motor control

longitudinal fissure

separates cerebral hemispheres

Structural divisions of the cerebrum

5 lobes separated by gyri, 2 hemispheres separated by longitudinal fissure

Functional Divisions of the Brain

Motor, Sensory, and Association

Primary Motor Cortex

Several adjacent and highly interconnected areas in the frontal lobe together mediate the planning and initiation of complex temporal sequences of voluntary movements.

premotor cortex

Involved in planning and organizing movements and actions. It precedes the activation of the primary motor cortex and is part of the brain region responsible for coordinating complex movement sequences. The region controls learned and repeated motor skills.

Broca's area

muscles of speech production

Regions of the cerebral motor cortex

primary motor cortex, premotor cortex, brocas area, frontal eye field

regions of sensory cortex

primary somatosensory cortex, somatosensory association cortex, visual cortex, auditory cortex, vestibular cortex, visceral sensory cortex, vestibular cortex, gustatory cortex, olefactory cortex

primary somatosensory cortex

general sensations in skin, proprioception of skeletal muscles joints and tendons, identification of region(s) of stimulation

Somatosensory association

Integrate sensory information input to produce understanding of what is felt such as size, texture etc.

visual cortex

visual information

auditory cortex

use vibration to interpret pitch, loudness, location etc.

olfactory cortex

involved in conscious awareness of odors

gustatory cortex

area of the brain that receives and interprets tastes from the tongue found in the insula

visceral sensory cortex

located in the insula and is involved in the conscious perception of visceral sensations (upset stomach, full bladder, urge to defecate, etc.)

vestibular cortex

responsible for conscious awareness of balance

Association cortex

regions of the cerebral cortex that integrate simpler functions to perform more complex functions includes the anterior association cortex, posterior association cortex, and limbic association cortex

anterior association cortex

Prefrontal cortex

Most complicated cortical area

Intellect, cognition

Logic, reasoning

Decision making

Behavior control

Working memory

Persistence

Planning

Development depends on social environment

posterior association cortex

Pattern and facial recognition

Position in space

Understanding written and spoken language

Binding sensory input into coherent whole

amygdala

recognizes angry and fearful facial expressions, assesses danger. Elicit fear response

cerebellum

the "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance

functions of the spinal cord

Provides two-way communication to and from brain, contains spinal reflex centers

spinal cord protection

Bone, meninges, and CSF

length of spinal cord

approx. 18 inches

cervical enlargement of spinal cord

supplies nerves to the shoulder and upper limbs

lumbar enlargement of spinal cord

nerves to pelvic region and lower limbs

ventral root of spinal cord

contains axons of motor neurons

dorsal root of spinal cord

contains axons of sensory neurons

dorsal root ganglia

contain cell bodies of sensory neurons

spinal nerve

A dorsal and ventral root of each spinal segment unite to form a.... there are 31 pairs

conus medullaris

end of spinal cord

fillum terminale

thin thread of fibrous tissue at end of conus medullaris, attaches to coccygeal ligament

cauda equina

collection of spinal nerves below the end of the spinal cord