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Ramos Carmen p. 5 "Nervous" (Major part of the brain and its…
Ramos Carmen p. 5 "Nervous"
Major part of the brain and its functions
Cerebrum (Cerebral Hemisphere): superior part of the brain made of left and right hemispheres. {Function}: responsible for voluntary or conscious activities. Allows us to remember, past, present, and future.
Diencephalon (Has 2 main parts): Thalamus {Function}: relays sensory info, recognizes bad/good sensations. Hypothalamus {Function}: controls body temp. water balance, metabolism, etc.
Brain Stem - Midbrain{Function}: reflex center for vision and hearing- Pons{Function}: relay between cerebrum and crebellum- Medulla oblongata{Function}: reflex center for heart rate, breathing, vomiting, and swallowing.
Cerebellum {Function}: controls equilibrium and balance (and posture) - coordinates muscles of body and move smoothly (voluntary movements).
Major functions of the Nervous System
Control Center of the body: Receives, processes, and interprets the messages then determines what output occurs.
Name of all the lobes and its functions
Frontal Lobe {Function}: Personality/emotions/intelligence/Attention/Concentration - Logic/Problem Solving
Parietal Lobe {Function}: Post-central Gyrus= Somatic Sensory Area - interprets sensory info.
Temporal Lobe {Function}: Hearing/Speech/Memory/ Sequencing and Organization.
Occipital Lobe {Function}: processes vision (visual cortex)
Major Subdivisions and Divisions of nervous
Two Main Divisions: 1. Central Nervous System (CNS) 2. Peripheal Nervous System (PNS)
(CNS) - Brain/Spinal Cord {Function} receive incoming sensory info/issues instructions. 2. PNS - nerves that extend from brain and spinal cord. {Function} spinal nerve carry impulses to and from spinal cord.
Classification of neurons
3 types:
[1] Sensory (afferent) neurons: impulses to spinal cord and brain from all parts of body.
[2.] Motor ( efferent) neuron: impulses away from brain and spinal cord to only 2 kinds of tissue (muscle and
[3.] Interneuron(central or connecting neruons): transmit impulses from sensory to motor neuron.
[ 3 types of neruon structure]
multipolar: many dendrites, one axon 2. bipolar- one dendrite and axon. (sensory) 3. unipolar - fused axon and dendrite (sensory)
Tissues (structure and function of neuron)
{Function} nerve cells/ relay electrical impulses throughout the body.
{Structure} - Dendrite: Portion of neuron that receives impulse and sends signal to the cell body./ Axon: conducts signal away from cell body.
Myelin: fatty substance that insulates signal. (allows signal to be sent faster) / Node(s): of Ranvier spaces between myelin/ Schwann cells.
layers of meninges
Def: three layers of tissue that cover and protect the brain.
Outer layer: Dura Mater (tough mother)
Middle: Arachnoid mater (looks like cobweb)
Inner: Pia mater (gentle mother) covers every folds of the brain.
Spaces and their ventricles
Neural canal enlarges in 4 areas of brain, forming ventricles. Ventricles are ependymal brain cavities.
Subarachnoid space: surrounds the central nervous system
Lateral ventricles: occupies the central hemisphere. Both connected to the third ventricle at the center of the diencephalon. (By Foramina Monro)
Third ventricle connected to the 4th ventricle at the brainstem. (By aqueduct Sylvius)
CSF leaves 4th ventricle through foramen of Magendie to fill the sub-arachnoid space between pia mater and arachnoid.
Link Title
Major parts and functions of spinal cord
{Functions}: [1] Contains centers for thousands of reflex arcs. {interneuron: transfers sensory impulses to outgoing motor impulses} {spinal cord reflex: reflex from conduction over arcs in spinal cord -1) Withdrawal reflex 2)Jerk reflex
{Functions}: Carries impulses to and from the brain. {A - Ascending tracts: send sensory impulses to brain. B- Descending tracts: send motor impulses down}
{Parts} -( Inner portion)H-Shaped core made of gray matter: dendrites and cell bodies of neuron. (Outer portion) made up of white matter which is spinal tracts: bundles of myelinated nerve fibers.
Diseases associated with the brain
Contusion: causes permanent tissue damage.
Intracranial hemorrhage- bleeding in the skull, edma. (Shaken Baby Syndrome)
Dementia ("forgetfulness")- loss of brain function. Affects memory, language, cognitive skills, and attention span.
CVA- (cerebrovascular accident {stroke}) blood flow to the brain tissue is blocked causing cell death. [ Hemorrhagic stroke and Ischemic stroke] - weakened/ diseased blood vessels rupture/blood leaks into brain tissue/ blood clots stop the flow of blood to an area of brain.
Drugs that affect the brain
Heroine: Shuts down release of inhibitory neurotransmitters. Creates feeling of sedation and well-being.
Ecstasy: Mimics serotonin and taken up by its transports. Affects mood, sleep, perception, and appetite.
Marijuana: turns off release of inhibitoy neurotransmitters. Dopamine enters synapse. Makes person feel released and happy.
Meth: Causes excess dopamine and reverse work for transporters. Overstimulates cell. Makes user feel intense pleasure and exhilaration.
Alcohol: interacts with GABA receptors and make them more inhibitory. Binds glutamate receptors preventing to exit the cell. Effects memory formation, decision-making, and impulse control.
Cocaine: blocks transporters which traps dopamine to synpatic cleft. Overstimulates cell. Makes user feel fidgety and can't be still.
LSD: Actively affects serotonin neruons. Inhibits and sometimes exictes receptors. Brings complex sensory effects. Creates wakefulness abd startled response to unexpected stimulus.
Division of the PNS
nerves that extend from brain and spinal cord
2 DIVISIONS:
Sensory (afferent) nerves : relay info from skin, muscles, and glands to CNS. (Interneuron - nerves that connect sensory nerves to motor nerves)
Motor (efferent) nerves - carry impulses from CNS to organs, muscles (they cause an effect or response).
Anatomy of the Spinal Cord
Base of Skull
Cervical enlargement
Lumbar enlargement
Conus medullaris(termination of spinal cord)
Internal filum terminale of pia mater.
Termination of dura sac
External filum terminale of dura mater
Coverings
made up of fibrous connective tissue
<---Types
Endoneurium - surrounds individual fibers within a nerve
Fasicle - a group of nerve fibers (group of wrapped axons)
Perineurium - surrounds a group of nerve fibers (surrounds fascicle)
Epinerurium- surrounds entire nerve
Neurotransmitters: chemical compounds released from axon terminals (presynaptic neuron) into synpatic cleft.
Function: binds to specific receptor molecules in membrane of postsynaptic neuron. Opens ion channels and stimulates impulse conduction by membrane.
Compare and contrast the autonomic nervous system
Autnomic nervous system (location): heart, iris, and stomach. / Somatic(location): vision, hearing, and touch.
Autonomic (involuntary) motor nerves/ Somatic (voluntary motor nerves)
Autonomic and Somatic are both 2 types of motor neurons that carry impulses from the CNS to organs, muscles (they cause an effect or response)
Autonomic sensory neurons respond to the internal environment from the CNS. As Somatic respond to the external environment.
Reflex arc
pathway of reflex response
<-- 5 part steps
sensory receptor ---> nerve ending detects stimulus
sensory/afferent neuron ---> sends signal to CNS.
synapse/interneuron integration center -> connection between sensory neuron and motor neuron.
motor neuron -> delivers response to target organ
effector -> target organ responds to signal
Action Potential
Nerve impulse is transmitted during action potential. (-70mV -> +30mV)
1) Strong enough stimulation causes Na+ gates to open => Na+ rush into cell causing depolarization. - more sodium ions outside/ - more pos. ions move in = "neutralize"
2) Strong enough depolarization = threshold potential is reached and impulse is sent down axon.
3)K+ rush out of neuron after Na+ rushes in, repolarizes membrane.
4.) Membrane is hyperpolarized - too many Ka+ leave the cell. Membrane potential dips below resting potential.
