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Nervous System by David Love Per 4 (Parts of Brain (Main parts of the…
Nervous System by David Love Per 4
Functions
The nervous system collects sensory inputs from the body.
It then processes and interprets the inputs.
It then activates an effector muscle or gland to respond to input.
Divisions
Two main divisions of the nervous system are the
Central Nervous System(CNS)
and the
Peripheral Nervous System (PNS)
. The CNS consists of the brain and the spinal cord. The PNS consists of the ganglion and the nerves.
PNS
Further divided into two divisions: sensory (afferent) and motor(efferent)
Sensory
- Includes nerves that send impulses to CNS for integration. Also detects stimuli inside and outside of body.
Motor
- Includes nerves that carry impulses away from CNS. Subdivided into
Somatic Nervous System(SNS)
and
Autonomic Nervous System(ANS)
.
SNS
- Voluntary motor response that invloves contraction of skeletal muscles. Ex: reflexes.
ANS
- Involuntary response usually to maintain homeostasis. Its main function is to regulate the organ systems. Ex: control of sweat glands. Subdivided into sympathetic and parasympathetic division.
Sympathetic
- Associated with fight-or-flight response.
Parasympathetic
- Associated more with rest and digest.
Parts of Brain
Main parts of the brain are the cerebrum, brainstem, and cerebellum.
Cerebrum
- Divided into two hemispheres connected by corpus callosum and four lobes.
Brainstem
- Consists of the midbrain, pons, and medulla.
Cerebellum
- Located on lower back of brain. Main function is to maintain posture and balance.
Pons
- Deals with eye and face movements.
Medulla
- Holds control centers for heart and lungs.
Spinal Cord
- Carries messages from and to brain to body.
Thalamus
- Relays sensory information from parts of body to cerebral cortex.
Hypothalamus
- Regulates functions in the pituitary gland and endocrine system.
Cranial Nerves
Olfactory
- Transmits sensory information dealing with smell.
Optic
- Involved with vision.
Oculomotor
- Deals with muscle function and pupil response.
Trochlear
- Deals with eye movements.
Trigemenial
- Deals with info and functions of the face.
Abducens
- Deals with muscle that is associated with eye movement.
Facial
- Provides facial expressions.
Vestibulocochlear
- Help with sound detection and balance.
Glossopharyngeal
- Provides taste.
Vagus
- Deals with taste communication, and stimulation.
Accessory
- Controls neck muscles.
Hypoglossal
- Movement of tongue
Drugs
Alcohol- Makes GABA receptor more inhibitory and affects memory formation and impulse.
Cocaine- Leaves dopamine overstimulating cell and affects voluntary movement.
LSD- Either inhibits or excites receptors and evokes wakefulness.
Heroine- Activates opiate receptors and gives person feeling of sedation.
-Ecstasy- Mimics serotonin and affects mood,sleep, and perception.
Marijuana- Releases inhibitory transmitters and slows down movement.
Meth- Forces dopamine out of vesicle and makes person feel pleasure and exhilaration.
Lobes
Frontal
- Most anterior part of the brain. Deals with cognitive functions like problem solving, memory, language, etc.
Occipital
- Most posterior lobe. Deals with vision.
Parietal
- Deals with processing sensory information.
Temporal
- Deal with short-term memory and speech.
Meninges
Meninges are the layers of CT that protect brain and spinal cord.
Dura Mater
- Outermost layer beneath the bones of the skull. Consist of the periosteal and menigeal layer.
Arachnoid
- Connects dura mater and pia mater.
Pia Mater
- Closely covers the cerebral cortex and the spinal cord.
Ventricles
Ventricles are cavities in the brain that remove cerebrospinal fluid. The lateral ventricles are located within the two brain hemispheres. The third ventricle is between right and left thalamus. The fourth ventricle is between the pons and medulla and receives cerebrospinal fluid from third ventricle.
Neurons
Multipolar
- Have three or more processes.
Bipolar
- Have two processes: an axon and dendrite.
Unipolar
- Have single short process.
Sensory
- Transmit impulses from sensory receptorsinternal organs towards CNS
Motor
- Carry impulses away from CNS to effector organs.
Interneurons
- Shuttle signals through CNS pathways.
Astrocytes
- Most abundant glia cells that help support neurons.
Microglial
- Transforms intophagocytic macrophage that help clean neurons waste.
Ependymal
- Form peamable barriers in central cavities of brain and spinal cord.
Oligodendrocytes
- Form myelin sheaths.
Satellite
- Surround neuron cell bodies in the PNS.
Schwann
- Form myelin sheaths around nerve fibers.
Spinal Cord
Spinal cord is part of CNS and has 31 segments:8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal. Spinal cord relays messages to parts of body to perform an action. Also coordinates reflexes
Neurotransmitters
Acetylcholine
- Control muscle contraction, memory, etc.
Serotonin
- Involved with regulation of sleep.
Dopamine
- Regulate movement and pleasure.
GABA
- Inhibits firing of neurons.
Glutamate
- Strengthens synaptic connection between neurons.
Endorphin
- Moderate pain.