anatomy exam 4

what are the functions of the nervous?

communication and coordination in site of reasoning (brain)

neurons

structural units of nervous system

dendrite

motor neurons can contain 100s of these shirt, tapering, diffusely branched process

axon

carry impulses away from cells

sensory (afferent) neurons

carry nerve impulses, message from stimulus to brain

motor (efferent)

carry nerve impulses message from brain to muscle

what are the functions of myelin?

* protects and electrically insulates axon
* increases speed of nerve impulse transmission

Myelin sheath

composed of myelin, whitish, protein lipid substance and segmented sheath around most long or large diameter axon

node of ranvier

myelin sheath gaps between adjacent Schwann cells, sites where axons collateral can emerege

Astrocytes

 most abundant, versatile and highly branched glial cells. Cling to neurons, synaptic endings and capillaries. 

Function for Astrocytes

support and brace neurons, play role in exchanges between capillaries and neurons, respond to nerve impulses and neurotransmitters     

Microglial Cells

 small, ovoid cells with thorny processes, migrate toward injured neurons

Macrophage

 can transform to phagocytize microorganisms and neuronal debris.

Ependymal Cells

\
* **Range in shape from squamous to columnar** 
* Ciliated - cilia beat to circulate CSF
* **Line the central cavities of the brain and spinal column**    

Oligodendrocytes

\
* **Branched cells - 15 arms**
* **Processes wrap central nervous system nerve fibers, forming insulating myelin sheaths.**     

Satellite Cells

urrounded neurons cell bodies in peripheral nervous system insulating it

Schwann Cells

surround all peripheral nerve fibers and form myelin sheaths in thicker nerve fibers. Similar function as __oligodendrocytes.__

the cerebral hemispheres

form superior part of brain and account for 83% percent mass

What are the surface marking for Cerebral Hemispheres?

* Gyri: ridges, increased surface area
* Sulci: shallow grooves
* Fissures: deep grooves

what are the 5 lobes several sulci divide each hemisphere into?

Gyri, sulci, fissures, longitudinal fissure, transverse cerebral fissure

Insular Lobe

buried under portions of temporal, parite

Longitude Fissures

separates two hemispheres

Transverse Cerebral Fissure

separates cerebrum and cerebellum

what are the3 regions each hemisphere is divided into?

Cerebral cortex of gray matter superficially, white matter internally,

Cerebral Cortex

executive suite of the brain,

conscious mind

neuron cell bodies, dendrites, glial cells, blood vessels, no axons

what are the 3 functioning areas of cerebral cortex?

Each Hemisphere is concerned with what?

What does the right hemisphere control?

Muscles on left side of the body

What does the left hemisphere control?

What does the conscious behavior involve?

The entire Cerebral Cortex

Frontal lobe

primary somatic motor cortex

located in precentral gyrus of frontal lobe

somatotpy

all muscles of body can be mapped to area on primary motor cortex

Premotor Cortex

helps plan movement. staging area for skilled motor activities. controls learned, repet

Brocas Area

present in one hemisphere (left). motor speech area that directs muscles of speech production

Frontal Eye Field

controls voluntary eye movement

Cerebral cortex: Sensory Areas

areas of cortex concerned with conscious awareness of sensation

Primary somatosensory cortex

receives general sensory information from skin, skeletal muscles, joints and tendons

somatosensory association cortex

integrates sensory input from primary somatosensory cortex for understanding of object. determines size, texture and relationship of parts of objects being felt

Primary auditory cortex

interprets information from inner ear as pitch, loudness and location

Auditory Association area

stores memories of sounds and permits of sound stimulus

Primary Visual Cortex

located on extreme posterior tip of occipital lobe. receives visual information from retinas

Visual association area

surrounds primary visual cortex. uses past visual experiences to interpret visual stimuli. ex: ability to recognize faces

Vestibular Cortex

Responsible for conscious awareness of balance

Olfactory Cortex

involved in conscious awareness of odors

Gustatory Cortex

involved in perception of taste

Visceral Sensory Area

conscious perception of visceral sensation, such as upset stomach or full bladder

Cerebral Cortex: Association Areas

receives inputs from multiple senses and send outputs to multiple areas. allows us to associate previous and current information

Anterior association area

Aka prefrontal cortex, involved with intellect, cognition, recall and personality. contains working memory needed for abstract ideas, judgement, reasoning, persistence and planning.

Posterior association area

large region. plays roles with recognizing patterns and faces and localizing us in space. involved in understanding written and spoken language. Wernicke’s area

Lateralization

division of labor between hemispheres. hemispheres are not identical. some neural functions or specialized to one side of the brain or the other.

cerebral dominance

refers to hemisphere that is dominated for language

left hemisphere

controls language, math and logic

right hemisphere

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

Cerebral white Matter

second of the three 3 basic regions of cerebral hemispheres. responsible for communication between cerebral areas and between cortex and lower central nervous system. consists of myelinated fibers bundled into large tract

Association fibers

horizontal running fibers that connect different parts of same hemisphere

commissural fibers

horizontal fibers that connect gray matter of two hemispheres

projection fibers

vertical fibers that connect hemispheres with lower brain or spinal cord

Basal Nuclei (Ganglia)

this of the 3 basic regions

* inner gray matter
* each hemispheres basal nuclei include: caudate nucleus, putamen, globes pallidus

what are the function of Basal nuclei?

* influence muscle movements
* play role in cognition and emotion
* filter out incorrect responses
* inhibit unnecessary movements

The Diencephalon consist of what three paired gray matter structures?

thalamus, hypothalamus, epithalamus

Thalamus

makes up 80% of diencephalon

Thalamus acts as a relay station for brain and body sorts, edits and relays what?

* impulses from hypothalamus for regulating emotion and visceral function
* impulses from cerebellum and basal nuclei to help direct motor cortices
* impulses for memory or sensory integration

Hypothalamus

located between the thalamus and contains infundibulum

chief homeostasis controls of hypothalamus

* control automatic nervous system
* physical responses to emotions

What are the function of the hypothalamus?

* regulate body temperature
* regulates hunger and satiety in response to nutrient blood levels
* regulates water balance and thirst
* regulates sleep-wake cycles

Epithalamus

contains pineal gland and forms roof of third ventricle and secrets melatonin that helps regulate sleep wake cycles

What are the three brain stem regions?

Midbrain, Pons,Medulla oblongata

what is the difference between the structure of Brain Stem and spinal cord?

similar in structure to spinal cord but contains nuclei embedded in white matter

The brain stem controls what?

automatic behaviors necessary for survival

The brain stem contains what?

fiber tracts connecting higher and lower neural centers

What is the nuclei of the brain stem associated with?

10 of the 12 pairs of cranial nerves

where is the midbrain located?

between the diencephalon and pons

what is the corpora quadrigemina of the midbrain?

visual reflex and auditory relay centers

What is the job of Pons?

to help maintain normal rhythm of breathing

What does the medulla oblongata do?

blends into spinal cord foramen magnum, contains fourth ventricle and chloride plexus

What is the functions of the medulla oblongata?

autonomic reflex center and function overlap with hypothalamus relays

Cardiovascular Center (medulla)

* adjust forcer and rate of heart contraction
* vasomotor center adjusts blood vessel diameter for blood pressure regulation

Respiratory center(medulla)

* generate respiratory rhythm
* control rate of depth of breathing

What does the cerebellum contain?

thin cortex of gray matter with distinctive treelike pattern of white matter called arbor vitae

where is the cerebellum located?

dorsal to pons and medulla

The cerebellar processing plays and important role in motor control involving what?

* muscle tone
* coordination
* balance and posture

What is the limit system?

emotional brain that structures on medial aspects of cerebral hemispheres and diencephalon. Also puts emotional responses to odors.

What is Amygdala?

recognizes angry or fearful facial expressions, accesses danger and elicits fear response

What is Cingulate Gyrus?

role in expressing emotions via gestures, and revolves mental conflict

What is Reticular Formation?

important role in controlling autonomic functions, consciousness and alertness and functions during sleep and arousal from sleep

Where is the reticular formation located?

central core of brain stems

What are the connections of the reticular formation?

axonal connections with hypothalamus , thalamus, cerebral cortex, cerebellum , and spinal cord. the connections allows it to govern brain arousal

What is the reticular activating system (RAS)?

* sends impulses to cerebral cortex to keep it conscious and alert
* filters out repetitive, familiar, or weak stimuli

What is the EEG?

it is how we study the brain, record electrical activity that accompanies brain function and measures electrical potential differences between various cortical area

Alpha Waves

8-13 HZ, regular and rhythmic, low amplitude, synchronous waves indicating and idling brain

Beta Waves

14-30 HZ, rhythmic less regular waves occurring when mentally alert

Theta Waves

4-7 HZ, more irregular common in children and uncommon in awake adults

Delta waves

4 HZ or less, high amplitude waves of deep sleep and when reticular activating system is damped as during anesthesia. indicate brain damage in awake adult

What is consciousness?

conscious perception of sensation that is voluntary initiation and control of movement. capabilities associated with high mental processing

What are sleep and wake cycles?

state of parietal unconsciousness that a person can be aroused by stimulation

What are the two major types of sleep?

* Non rapid eye movement sleep,


* rapid eye movement sleep- eyes oscillate back and forth

what happens the first 30-45 minutes of sleep?

pass through the first two stages of non rapid eye movement sleep (NREM)