Anatomy and Physiology: Chapter 12: The Central Nervous System

Cortex

"Bark" of gray matter which surrounds everything

4 Generalizations about Cerebral Cortex

1. Cerebral cortex contains 3 kinds of functional areas (motor, sensory, and association) 2. Each hemisphere is concerned with opposite side of body 3. Specialization of cortical functions 4. No functional area of cortex acts alone and conscious behavior involves the entire cortex in one way or another

3 Parts of Multimodal Areas

1. Prefrontal Cortex (anterior association area) 2.Posterior Association Area 3. Limbic Association Area

Basal Nuclei

3rd basic region of each hemisphere. A group of subcortical nuclei. Each hemisphere's basal nuclei include the caudate nucleus, putamen, and globus pallidus. Receive input from entire cerebral cortex via the thalamus. Influences muscle movements. Motor functions overlap with those of cerebellum. Play a role in emotion and cognition; seem to filter out incorrect or inappropriate responses. Starting/stopping and monitoring intensity of movements.

Posterior Association Area

Binding together different sensory inputs into a coherent whole; recognizing patterns/faces, localizing us and our surroundings in space

Hypothalamus

Caps the brain stem and forms the inferolateral walls of the 3rd ventricle; contains many functionally important nuclei. Main visceral control center of body and vitally important to overall body homeostasis.

3 Basic Regions

Cerebral Cortex of Gray matter, internal White Matter, and basal nuclei (islands of gray matter situated deep within white matter)

4 Adult Brain Regions

Cerebral Hemispheres, Diencephalon, Brain Stem (midbrain, pons, medulla) and Cerebellum

Third Ventricle

Communicate with each lateral ventricle via the inter ventricular foramen

Comissural Fibers

Connect corresponding gray areas of 2 hemispheres; allow 2 hemispheres to function as a coordinated whole; largest is the corpus callosum

Association Fibers

Connect different parts of the same hemisphere. Short connect adjacent gyri and long connect different cortical lobes

Vestibular Cortex

Conscious awareness of balance

Olfactory Cortex

Conscious awareness of different odors become part of "newer" emotional brain (limbic system)

Visceral Sensory Area

Conscious perception of visceral sensations

Diencephalon

Consists largely of thalamus, hypothalamus, and thalamus. Gray matter areas collectively enclose the 3rd ventricle.

Fourth Ventricle

Continuous with 3rd ventricle; communicates via the cerebral aqueduct that runs through the midbrain

Ventricles

Continuous with one another; filled with cerebrospinal fluid and lined with ependymal cells

Functions of Hypothalamus

Control ANS (blood pressure, heart beat, pupil size), emotional responses, regulates body temperature, regulates sleep/wake cycle, controls endocrine system function.

Frontal Eye Field

Controls voluntary movements of eyes

Cerebral White Matter

Deep to gray matter is responsible for communication between cerebral areas and between cerebral cortex and lower CNS centers. Consists largely of myelinated fibers bundled into large tracts; classified according to direction they run. Association, comissural, and projection

Fissures

Deeper grooves

Lateralization

Each hemisphere has abilities not completely shared by its partner

Projection

Either enter the cerebral cortex from lower brain/cord centers or descend from cortex to lower areas. Sensory information reaches the cerebral cortex and motor output leaves it through these projection fibers.

Gyri

Elevated ridges

Secondary Brain Vesicles

Forebrain becomes the telencephalon (end brain) and the diencephalon (inter brain). Hindbrain constricts forming the met encephalon and my encephalon

Cerebral Hemispheres

Form superior part of brain; median longitudinal fissure separates cerebral hemispheres. Transverse cerebral fissure separates the cerebral hemispheres from the cerebellum

Right Hemisphere Abilities

Free-spirited, visual-spatial skills, intuition, emotion, artistic and musical skills

5 Lobes

Frontal, Parietal, Occipital, and Insular

Premotor Cortex

Helps plan movements; select and sequences basic motor movements. Staging area for skilled motor activities

Limbic Association Area

Includes cingulate gyrus, parahippocamal gyrus, hippocampus. Provides emotional impact that makes a scene important to us

Epithalamus

Includes pineal gland (secretes melatonin) along with hypothalamus to regulate sleep/wake cycle

Path of Info

Information from sensory receptors to the appropriate primary sensory cortex. Then to the sensory association cortex. Then to multimodal association cortex, which allows us to give meaning to the information that we receive, store it, tie it to previous experiences/knowledge, decided what action to take. Relayed to premotor cortex which in turn communicates with motor cortex.

Somatosensory Association Cortex

Integrates sensory inputs relayed to it via primary somatosensory cortex to produce an understanding of an object

Central Nervous System

Is made up of by the brain and spinal cord

Primary Motor Area

Large neurons called pyramidal cells allow us to consciously control precise/skilled voluntary movements of skeletal muscles. Individual pyramidal motor neurons control muscles that work together in a synergistic way to perform a given movement.

Midbrain

Located between diencephalon and pons.

Brain Stem

Midbrain, pons, and medulla. Has nuclei of gray matter embedded in white matter; a feature not found in spinal cord. Rigid programmed autonomic behaviors necessary for survival. Also provides a pathway for fiber tracts running between higher and lower neural centers.

Prefrontal Cortex

Most complicated; intellect, complex learning abilities, recall, and personality, judgement/reasoning, planning, contains working memory

Gray Matter

Mostly cell bodies; does not contain myelinated axons

White Matter

Myelinated fiber tracts

Thalamus

One part of the diencephalon; "relay" center for information coming into cerebral cortex. Afferent impulses from all senses and all parts of the body converge on the thalamus and synapse with at least one of its nuclei. Information sorted out and "edited"; mediates learning and memory

Lateral Ventricles

Paired with one deep within each cerebral hemisphere; reflect pattern of cerebral growth

Auditory Areas

Primary auditory cortex interprets pitch, loudness, and location. Auditory association area permits perception of the sound stimulus. Memories of sound stored here

Motor Areas

Primary motor cortex, premotor cortex, Broca's Area, and frontal eye field

Sensory Areas

Primary somatosensory cortex, somatosensory association cortex, visual areas, auditory areas, olfactory cortex, gustatory cortex, and visceral sensory area

Visual Areas

Primary visual cortex receives visual information that originates on retina of eye. Vissual association area uses past visual experiences to interpret visual stimuli

3 Primary Brain Vesicles

Prosencephalon (forebrain), mesenchephalon (midbrain) and rhombencephalon (hindbrain)

Multimodal Association Areas

Receive inputs from multiple senses and sends outputs to multiple areas

Primary somatosensory Cortex

Receives information from general sensory receptors in skin and proprioreceptors skeletal muscles, joints, and tendons. Smaller, more sensitive areas occupy more space here

Sulci

Shallow grooves

Broca's Area

Special motor speech area directs muscles involved in speech production

Left Hemisphere Abilities

language abilities, math and logic