Sensory/afferent: impulses to CNS from receptors Motor/efferent: impulses from CNS to effector organs
Central nervous system
Brain and spinal cord Integrating and command centers Interpret incoming sensory information and issue instructions
Peripheral nervous system
Nerves Communication lines Link all parts of the body by carrying impulses
Star-shaped with swollen ends Protect neurons from harmful substances in blood Help control chemical environment in brain CNS
Spiderlike phagocytes Dispose of debris and dead brain cells CNS
Circulate cerebrospinal fluid Protective cushion around CNS Line cavities of brain and spinal cord
Flat extensions Produce myelin sheaths Wrap around nerve fibers CNS
Form myelin sheaths PNS
Protective, cushioning cells PNS
Cell body, nucleus, one or more processes Transmit messages
Dense myelinated fibers
Unmyelinated fibers and cell bodies
Most superior Gyri: elevated ridges Sulci: shallow groves Fissures: deeper grooves
Cerebrum - parietal lobe
Somatic sensory area Posterior to central sulcus Interprets impulses from sensory recetpros Recognize pain, coldness, touch
Cerebrum - occipital lobe
Cerebrum - temporal lobe
Auditory Olfactory Borders lateral sulcus
Cerebrum - frontal lobe
Primary motor area Anterior to central sulcus Conscious movement of skeletal muscles
Cerebrum - Broca's area
Speech Base of precentral gyrus
Interbrain Sits atop brain stem, enclosed by cerebral hemispheres
Diencephalon - thalamus
Encloses third ventricle Relay station for sensory impulses
Diencephalon - hypothalamus
Under thalamus Regulates body temperature, water balance, metabolism Center for drives and emotions Pituitary gland: produces hormones Mammilary bodies: reflex centers
Diencephalon - epithalamus
Roof of third ventricle Pineal body Choroid: forms CSF
Brain stem - midbrain
Mammillary bodies to pons inferiorly Reflex centers for vision and hearing
Brain stem - pons
Rounded structure below midbrain Mostly fiber tracts Control of breathing
Brain stem - medulla oblongata
Most inferior of brain stem Controls heart rate, blood pressure, breathing, swallowing, vomiting Posterior to pons and medulla, anterior to cerebellum
Dorsally from occipital lobe Timing for skeletal muscle activity Controls balance and equilibrium
Watery broth Contains less protein, more vitamin C Watery cushion protects nervous system from blows and trauma
Least permeable capillaries in body Separates neurons from bloodborne substances Useless against fats, respiratory gases, fat-soluble molecules
Meninges - dura mater
Tough mother Outermost layer Surrounds brain, attached to inner surface of skull
Meninges - arachnoid mater
Cobweb Middle layer
Meninges - pia mater
Gentle mother Innermost layer Clings tightly to surface of brain and spinal cord
Reflexes - reflex arc
Sensory receptor reacts to stimulus Effector organ eventually stimulated Sensory and motor neurons connect the two Integration center: synapse between sensory and motor neurons
Reflexes - somatic
Stimulate skeletal muscles Pulling hand away from hot object
Reflexes - autonomic
Activity of smooth muscles, heart, glands Digestion, elimination, blood pressure, sweating Secretion of saliva, changes in size of eye pupil
Fibers arise from olfactory receptors in nasal mucosa and synapse with olfactory bulbs. Carries impulses for sense of smell.
Fibers arise from retina of eye and form optic nerve. The two optic nerves from optic chiasma by partial crossover of fibers. Carries impulses for vision.
Fibers run from the midbrain to the eye. Supplies motor fibers to four of the six muscles that direct the eyeball, to the eyelid, and to the internal eye muscles controlling lens shape and pupil size.
Fibers run from the midbrain to the eye. Supplies motor fibers for one external eye muscle.
Fibers emerge from the pons and form three divisions that run to the face. Conducts sensory impulses from the skin of the face and mucosa of the nose and mouth; also contains motor fibers that activate the chewing muscles.
Fibers leave the pons and run to the eye. Supplies motor fibers to the lateral rectus muscle, which rolls the eye laterally.
Fibers leave the pons and run to the face. Activates the muscles of facial expression and the lacrimal and salivary glands; carries sensory impulses from the taste buds of anterior tongue.
Fibers run from the equilibrium and hearing receptors of the inner ear to the brain stem. Vestibular branch transmits impulses for the sense of balance, and cochlear branch transmits impulses for the sense of hearing.
Fibers emerge from the medulla and run to the throat. Supplies motor fibers to the pharynx that promote swallowing and saliva production; carries sensory impulses from taste buds of the posterior tongue and from pressure receptors of the carotid artery.
Fibers emerge from the medulla and descend into the thorax and abdominal cavity. Fibers carry sensory impulses from and motor impulses to the pharynx, larynx, and the abdominal and thoracic viscera; most motor fibers are parasympathetic fibers that promote digestive activity and help regulate heart activity.
Fibers arise from the medulla and superior spinal cord and travel to muscles of the neck and back. Mostly motor fibers that activate the sternocleidomastoid and trapezius muscles.
Fibers run from the medulla to the tongue. Motor fibers control tongue movements; sensory fibers carry impulses from the tongue.
Spinal nerve plexuses - cervical
C1-C5 Phrenic: diaphragm and muscles of shoulder and neck
Spinal nerve plexuses - brachial
C5-C8 and T1 Axillary: deltoid muscle of shoulder Radial: triceps and extensor muscles of forearm Medial: flexor muscles of forearm and some muscles of hand
Spinal nerve plexuses - lumbar
L1-L4 Femoral: lower abdomen, buttocks, anterior thighs, skin of anteromedial leg and thigh Obturator: adductor muscles of medial thigh and small hip muscles, skin of medial thigh and hip joint
Spinal nerve plexuses - sacral
L4-L5 and S1-S4 Sciatic: lower trunk and posterior surface of thigh Common fibular: lateral aspect of leg and foot Tibial: posterior aspect of leg and foot Superior and inferior gluteal: gluteus muscles of hip
Collection of nerve fibers in CNS having the same origin, termination, and function
Dense central body in most cells containing genetic material of cell