EXAM 5

Sensory Input

* gathering information
* monitor changes occurring inside and outside the body (changes = stimuli)

Integration

to process and interpret sensory input and decide if action is needed

Motor Output

* a response to integrated stimuli
* the response activates muscles and glands

Central Nervous System

* brain
* spinal cord

Peripheral Nervous System

nerves outside the brain and spinal cord

* spinal nerves
* cranial nerves

Sensory (afferent) division

nerve fibers that carry information to the CNS

Motor (efferent) division

nerve fibers that carry impulses away from the CNS

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Somatic (voluntary)

skeletal muscles

Autonomic (involuntary)

smooth muscles and glands

* sympathetic


* parasympathetic

Autonomic nerves

normally work antagonistically

Parasympathetic Nerves

dominate when there is little outside stimulation

Sympathetic Nerves

* dominate during a state of heightened awareness
* fight or flight response

Neurons

communication specialists

composed of:

* dendrites
* cell body
* axon

3 types of neurons

1. sensory neurons (receiving information carrying through)
2. interneurons (messenger)
3. motor neurons (response)

electoral gradient

across a plasma membrane

* ions cross the membrane passively and actively -
* gated and open channel transporters

resting membrane potential

change difference has the potential to do physiological work

* electoral gradient gives you the potential to do something

Nerve Impulses

= action potentials

* an action potential is generated when a signal causes the resting membrane potential to reverse
* an action potential causes the inside of the cell to be more positive
* called depolarization of the membrane

Resting neuron

the membrane at rest is polarized

* more positive ions are outside the cell than inside the cel
* creates an electric gradient

Depolarization of the membrane

1. A stimulus depolarized the neurons membrane
2. Allows for sodium (Na+) to flow inside the cell
* this exchange of ions imitates and action potential in the neuron
3. Once action potential starts, it is propagated over the entire axon

Repolarization

4. Potassium ions (K+) rush out of the neuron which depolarizes the membrane
5. The sodium potassium pump restores the original configuration

Neurotransmitters

action potentials may cause a neuron to release ______ at the axon terminals

* signaling molecules that diffuse to a receiving cell
* the signal is received by receptors on neighboring (post synaptic) neuron
* information flows from cell-cell
* chemical signal that diffuse across a synapse
* between two neurons
* between a neuron and a muscle or a gland cell

Presynaptic Cells

vesicles of neurotransmitter

Postsynaptic Cells

receptors of a neurotransmitter

How neurons communicate

1. Diffusion
2. Acetylcholinesterate
3. Membrane transport proteins

Altering Synaptic Transmission

many common chemical substances after synaptic transmission

* insecticides anesthetics
* antidepressants
* caffeine
* cocaine

Myelin Sheath

* axon insulation and propagation of the signal
* glial cells
* schwann cells

Reflex

* always the same response to a particular stimulus
* rapid, predictable, involuntary response to a stimulus

Reflex Arcs

* sensory arcs synapse directly on motor neurons
* interneurons may (or may not) be involved

The Brain

* weighs \~1,300 g (3 lbs)
* most protected organ in the body

has:


1. Cranial Bones (skull)
2. Meringes
3. Cerebrospinal fluid

Meninges

1. Dura Mater
2. Arachnoid (webbing connective tissue)
3. Piamater

Cerebrospinal Fluid

* formed in blood plasma
* in brain ventricles, space between innermost meninges and brain, and central Canal of spinal cord

Meningitis

* inflammation of the meninges
* sample CSP for diagnosis

Blood brain barrier due to

structure of capillaries

* most impermeable

Hindbrain

* medulla oblongata
* cerebellum
* pons

Medulla Oblongata

reflex center for vital tasks

Cerebellum

coordinates movement and balance

pons

directs signals between cerebellum and forebrain

Midbrain

coordinates reflex responses to sight and sound

Forebrain

* cerebrum
* olfactory bulbs
* thalamus
* hypothalamus

Cerebrum

information processing

Olfactory bulbs

smell

Thalamus

sensory relay

Hypothalamus

homeostasis, emotions, and sexual behavior

Cerebrum

* capacity for conscious thought and language arises from eh actively off cerebral cortex
* cortex interacts with the brain regions to shape our emotional responses and memories

Cerebral Cortex

* outer gray matter, deeply folded
* inner white matter and basal nuclei

Corpus callous

band of never tracts

* receive signals from the opposite side of the body

The left and right hemispheres are ___

distinct

Right hemisphere

* analyzes sensory input
* recognizes faces
* functions in spatial relationships

Left Hemisphere

* general language interpretation and speech
* controls writing and speaking
* categorizes items and makes logical decisions

Motor Areas

controls coordinated movements of skeletal muscles

Premotor Cortex

learned patterns of motor skills

Brocas Area

controls muscles necessary for speech

Frontal eye field

controls voluntary eye movement

Sensory areas

including sounds, odor, and tastes

Frontal

primary motor

Occipital

vision

Temporal

auditory

Parietal

somatosensory

Learning

acquisition of new information and skills

Memory

storage and recall of information

Short-term memory

may involve temporary changes in the function of synapses

Long-term memory

may involve permanent structural and functional changes

GABA

inhibits release of the neurotransmitters

Axon

where electrical impulses from the neuron travel away to be received by other neurons

Axon Terminal

axon ending that are somewhat enlarged and often club- or button-shaped

Cell Body

nucleus containing central part of a neuron exclusive of its axons and dendrites that is the major structural element of theory matter of the brain and spinal cord, the ganglia, and the retina.

Conducting Zone

Contains all the structures that provide passageways for the air to travel into and out of the lungs

Dendrite

membraneous tree0like projections arising from the body of the neuron

Depressants

an agent or remedy which lowers the vital powers

Dopamine

type of monamine neurotransmitter made in the Brian acting as a chemical messager

Drug

anything that is used to produce physiological or physiological effects

epinpherine

hormone mainly secreted by the medulla of the adrenal glands and increases cardiac output and raises glucose levels in blood

Hallucinogens

class of psychoactive drugs that produce altered states of consciousness characterized by major alterations in thought, mood, and perception as well as other changes.

Input zone

tapering region between a cell body and axon of a neuron

Narcotics

substance used to treat moderate to severe pain

Nerve

bundle of fibers that receives and sends messages between the body and brain

Potassium

regulation of blood pressure and water content in cells, transmission of nerve impulses, digestion, muscle contraction, and heartbeat.

Resting membrane

electrical potential inside the cell relative to the adjacent extracellular space

Potential

different ein electric potential between the interior and the exterior of a biological cell

Serotonin

found in digestive tract; focused, emotionally stable, happier, and calmer

Sodium

maintenance of normal cellular homeostasis and in the regulation of fluid and electrolyte balance and blood pressure

solute pump

form of active transport of a solute through a cell membrane

stimulants

promotes increase soft microorganism populations by enhancing the environment in which they live and providing food for them to consume

Vesicle

a small fluid filled bladder, sac, cyst, or vacuole within the body.

Somatic Senses

touch, pressure, temperature, pain

Special Senses

* chemical (taste and smell)
* light (vision)
* mechanical (hearing + equilibrium)

Sensory Receptors and Pathways

all convert to nerve impulses

strong stimulus = fire nerve impulses more often

weak stimulus = fire less often

the stronger the stimulus the more receptors respond

Sensory Adaptation

diminishing response to an ongoing stimulus

Somatic Receptors

free nerve endings: in the epidermis and many connective tissues

* detect touch, pressure, heat, cold, or pain

Merkel’s discs

steady touch

Meissner’s corpuscles

light touch

Ruffini endings

pressure, touch

Pacinian corpuscles

deep pressure

Somatic Receptors

send signals to the somatosensory cortex

located in various parts of the body

* near the body surface
* in skeletal muscles
* in walls of soft internal organs

Chemical Senses

taste and smell

Outer ear

sound waves enter and set up vibrations

Inner ear

different sound frequencies stimulate different patches of receptors

Middle ear

vibrations are amplified

Organ of Corti

located in the cochlea

receptors = hair like cells on the Basilian membrane

gel-like tectorial membrane bends hair cells

cochlear never transmits nerve impulses to auditory cortex on temporal lobe

Vestibular apparatus

* equilibrium organ in the inner ear
* fluid-filled semicircular canals
* role of sensory hairs and otoliths
* impulses go to reflex centers in the brain stem