EXAM 4 (ch.12-14) - Dr. Jones

sensory receptors

specialized to respond to changes in environment (stimuli)

sensation

awareness of stimulus

perception

interpreting meaning of stimulus

mechanoreceptors

respond to touch, pressure, vibration, and stretch

thermoreceptors

sensitive to change in temperature

photoreceptors

respond to light energy

ex.retina

chemoreceptors

respond to chemicals

eg. smell, taste, change in blood chemistry

nociceptors

sensitive to pain-causing stimuli (INTENSE stimulation)

eg. extreme cold/heat, excessive pressure, inflammatory chemicals

exteroceptors

respond to stimuli arising outside body

(most special sense organs)

-receptors for touch, pressure, pain, temp

interceptors

visceroceptors

-respond to stimuli arising in organs and blood vesels

proprioceptors

respond to stretch in skeletal muscles, tendons, joints, ligaments..

-inform brain of one’s movements

somatosensory system

part of sensory sytem serving body wall and limbs

-recieves inputs from Exteroceptors, Proprioceptors, and Interoceptors; input relayed TOWARD head, but processed along the way

adaption

change in sensitivity in presence of CONSTANT STIMULUS

inhibitory endogenous opioids

pain impulse blockage; protective action by body

eg. endorphins

visceral pain

stimulation of visceral organ receptors

-felt as vague aching, gnawing, burning

referred pain

pain from one body region percieved as coming from a diff. regionn

-visceral and somatic pain fibers travel along same nerves which cause brain to assume stimulus comes from common (somatic) region

nerve

- cordlike organ that is part of the peripheral nervous system

- classified as cranial or spinal

- consists of bundles of peripheral axons enclosed by of connective tissue

endoneurium

- layer of loose connective tissue that also encloses the fibers associated with Schwann Cells

perineurium

- coarser connective tissue wrapping

- binds groups of axons

epineurium

- tough fibrous sheath

- encloses all the fascicles to form the nerve

fascicles

groups of axons binded by perineurium are called...

mixed nerves

- contain both sensory and motor fibers and transmit impulses both to and from the central nervous system
- most are mixed (both sensory and motor)

ganglia

- collections of neuron cell bodies associated with nerves in the PNS

automatic nervous system

(Part of the Motor Division of the PNS)
Made up of the Sympathetic Division and the Parasympathetic Division

-maintains homeostasis

difference of automatic nervous system and somatic nervous system

-effectors

• Somatic NS : innervate skeletal muscles

• ANS: inervates cardiac muscle, smooth muscle, and glands

-number of neurons in charge of transmission

-neurotransmitters depend on target

parasympathetic division

promotes maintenance functions, conserves energy

sympathetic division

mobilizes body during activity

dual innervation

all visceral organs are served by both parasympathetic and sympathetic divisons

-conserve energy or mobilize for action

parasympathetic divison

rest-and-digest

-ppupils constricted

-direct digestion, diuresis, defecation

sympathetic division

fight or flight system

-excitement, emergency

-dilated pupils

-shunt blood to skeletal muscles and heart

-cause liver to release glucose for muscles

sympathetic division

increase heart and respiratory rates and inhibits digestion and elimination

parasympathetic division

decreases heart and respiratory rates and allows for digestion and discarding of wastes

nerves

bundle of axons in PNS

cephalization

concentration of nervous tissue in the head

1. cerebral hemispheres

2. diencephalon

3. brain stem

4. cerebellum

what are the adult brain 4 regions?

midbrain, pons, medulla oblongata

what does the brain stem consist of?

gray matter

NON-MYELINATED NEURONS and cell bodies

white matter

MYELINATED and NONMYELINATED AXONS

-fat/lipid with protein

basic pattern found in CNS

central cavity SURROUNDED by GRAY MATTER, WHITE MATTER external to GRAY MATTER

(pattern change ascending brain stem)

cortex

what the cerebral hemispheres (cerebrum) and cerebellum contain OUTER LAYER OF GRAY MATTER

spinal cord pattern

-inner gray matter

-outer white matter

cerebrum and cerebellum pattern

-islands of gray matter (nuclei) within white matter

-cortex of gray matter

ventricles

filled with cerebrospinal fluid

-lined with ependymal cells (neuroglial cells)

-paired lateral ventricles separated by membranous septum pellucidum

diencephalon

where third ventricle lies in

cererbral aqueduct

how third ventricle is connected to fourth ventricle

cerebral hemispheres

form superior part of brain

-account for majority of brain mass

gyri

ridges

sulci

shallow grooves

fissures

deep grooves

longitudinal fissure

seperates two hemispheres

transverse cerebral fissure

seperates cerebrum and cerebellum

insula

lobe buried under portions of temporal, parietal, and frontal lobes

-not visible on surface

central sulcus

Separates precentral gyrus of frontal lobe and postcentral gyrus of parietal lobe

parieto-occipital sulcus

Separates occipital and parietal lobes

lateral sulcus

outlines temporal lobes

each hemisphere’s basic regions

-cerebral cortex of gray matter on surface

-internal white matter

-basal nuclei deep within white matter

cerebral cortex

“executive suite” of the brain

-site of CONSCIOUS MIND: awareness and sensory perception

4 considerations of CEREBRAL CORTEX

1. Motor areas: control voluntary movement

2. Sensory areas: conscious awareness of sensation

3. Association areas: integrate diverse info into all one unique event

4. Lateralization: (specialization) of cortical function occure in only ONE hemisphere

contralateral

opposite (side of body)

primary (somatic) motor cortex

stimulate skeletal muscle

-pyramidal cells: large neurons in charge of allowig control of precise, skilled skeletal muscle movement

premotor cortex

helps plan movements

-ctrl learned, repeated, or patterned motor skills

broca’s area

in charge of communication; physically initiate speech and forming words

-planning speech

frontal eye field

control voluntary eye movements

stroke or muscle paralyzation

damage to PRIMARY MOTOR CORTEX results in…

neural plasticity

ability of brain to change its function by changing its structure

-brain can rewire in certain cases to maintain function

primary somatosensory cortex

recieve sensory info from skin and proprioceptors (relating info relation to body position) of skeletal muscle, joints, tendons

primary somatosensory cortex

capable of SPATIAL DISCRIMINATION: identification of body region being stimulated (what is the cortex?)

somatosensory association cortex

organize sensory neurons and understand object of sensation

somatosensory association cortex

determines size, texture, and relationship of parts of objects being felt is the function of what cortex?

primary visual (striate) cortex

bipolar retina neuron = perceve changes in light

-recieve info from retinas

visual association area

-surrounds primary visual cortex

-uses past visual exp. to interpret visual stimuli

ex. ability to recognize faces

primary auditory cortex

interpret info from inner ear as pitch, loudness, location

-what u hear

auditory association area

store memories of sounds and allows perception of sound stimulus

-what the sound means

vestibular cortex

responsible for conscious awareness of balance (position of head in space)

-Consciously aware of position

primary olfactory cortex

-conscious awareness of odors

-primative rhinencephalon, smell baby, food..

gustatory cortex

perception of taste

*taste and smell go together

visceral sensory area

Perceive fullness or stretch of organs

anterior of brain

where can you find motor areas of the brain?

posterior of brain

where can you find sensory areas of the brain?

damage to primary visual cortex

functional blindness; patient can see but do not comprehend what they are looking at

multimodal association areas

recieve inputs from multiple sensory areas and send outputs to multiple areas ex. we hear before we see

-gives meaning. connection to sensation, thoughts, emotions; makes us who we are

stages sensory receptors take through the brain

sensory receptors > primary sensory cortex > sensory association cortex > multimodal association cortex

prefrontal cortex / anterior association area

-unique personality

-form working memory

-reason + judgement

posterior association area

recognizing patterns and faces and localizing us in space

-”do i know what im looking at and where it is in relation to me?”

limbic association area

provides emotional impact that helps establish memories

cerebral dominance

hemisphere that is dominant for language (most humans have left sides dominance in brain, meaning they use right side of their body more)

lateralization

division of labor between hemispheres

-hemispheres are not identical

left hemisphere

control language, math, logic

(what is the hemisphere?)

right hemisphere

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

(what is the hemisphere?)

association fibers

horizontal running fibers that connect different parts of the same hemisphere

(white matter)

commissural fibers

horizontal fibers that connect gray matter of two hemispheres

projection fibers

vertical fibers that connect upper hemispheres with lower brain or spinal cord

basal nuclei

minimize unnecessary behaviors

-influence muscle movements, play role in cognition and emotion

Parkinson’s and Huntington’s disease

disorders of basal nuclei

-eg.. tremors

thalamus, hypothalamus, epithalamus

what are the 3 paired gray matter structures in the Diencephalon

thalamus

relay station for information coming in the cortex (afferent + efferent)

-sorts, edits, relays ascending input

-EVERYTHING goes through EXCEPT olfactory (smell) >goes to olfactory cortex

hypothalamus

-influences how endocrine system work

-maintains homeostasis of automatic nervous system (blood pressure, response to emotion), AND part of limbic system(pleasure, fear)

-regulate body temp, hunger/satiety, water balance/thirst, sleep-wake cycle

epithalamus

-contains pineal gland (secretes melatonin to regulate sleep-wake cycle; fall sleep)

automatic behaviors necessary for survival

what does the brain stem control?

superior colliculi

-connect to corpora quadrigemina

visual reflex centers

-Reflexive action to what you see