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Hondros A&P 1 Final

Terms in this set (89)

CNS
Central Nervous System; Brain and Spinal Cord
PNS
Peripheral Nervous System; Cranial, Spinal Nerves and Sensory Receptors
Reflexes
Rapid, involuntary and predictable responses to internal and external stimuli
Somatic Nervous System (SNS)
Voluntary (conscious) control of skeletal muscles
Autonomic Nervous System (ANS)
Involuntary (unconscious) control of cardiac muscle, smooth muscle and glands
Cell Body
Portion of a neuron that contains the large, spherical nucleus
Dendrites
Carries impulses TOWARD the cell body and axon
Axon
Carries impulses AWAY from the cell body or dendrites
Axon Terminals
One or more side branches (of an axon) that forms a number of short, fine branches at its tip
Synaptic Knobs
The slightly enlarged tips of the axon terminals which form junctions with other neurons, muscles, or glands
Myelin Sheath
The fatty insulating substance around many axons
Nodes of Ranvier
A space between adjacent Schwann cells wrapped around a neuron process
Schwann Cell
Only in PNS; Tightly wrapped myelin forces nucleus to outer portion; Outermost layer=Neurolemma
Neuron Physiology
Resting
Depolarization
Repolarization
Irritability
The ability to respond to a stimuli by forming an impulse
Conductivity
The ability to transmit an impulse along a neuron to other neurons, muscles, or glands
Resting Potential
Sodium (Na+) ions are outside the cell membrane and Potassium (K+) ions are inside the cell membrane
Depolarization
The inside is positively charged, the outside is negatively charged and both Sodium (Na+) and Potassium (K+) are inside the cell; Creates the nerve impulse
Repolarization
After depolarization, Potassium (K+) diffuses outward to reestablish the charge distribution of the resting state; Positive outside, negative (less positive) inside; Sodium (Na+) is the pumped out and K+ is pumped in to reestablish ion distribution of the resting state (Na+ outside and K+ inside)
Presynaptic Neuron
The synaptic knob is the first nerve impulse
Meninges
Consists of 3 membranes arranged in layers: Pia Mater, Arachnoid Mater, Dura Mater
Pia Mater
Inner membrane of the meninges
Arachnoid Mater
Middle membrane of the meninges
Dura Mater
Outer membrane of the meninges
Postsynaptic Neuron
Neuron that receives signal
Frontal Lobe
Higher level processing, practiced motor skills; Lies anterior to the central sulcus and superior to the lateral sulcus
Parietal Lobe
Detailed sensory processing; Lies posterior to the central sulcus, superior to the temporal lobe and anterior to the occipital lobe
Temporal Lobe
Hearing; Lies inferior to the frontal and parietal lobes and anterior to the occipital lobe
Occipital Lobe
Sight; Lies posterior to the parietal and temporal lobes
Left Hemisphere
Analytical and verbal skills
Right Hemisphere
Musical, artistic, spatial awareness, imagination and insight
Diencephalon
Lies between the brain stem and the cerebrum of the brain and consists of the Thalamus and Hypothalamus
Thalamus
Receives all incoming sensory impulses (except smell) after sending them to the cerebral cortex
Hypothalamus
Regulates body temperature, mineral and water processes, appetite and digestive processes, heart rate and blood pressure, sleep and wakefulness, emotions of fear and rage, and secretion of hormones by pituitary gland; Primary function is to maintain Homeostasis
Gyri
Folds
Sulci
Shallow grooves
Brain Stem
Midbrain
Pons
Medulla Oblongata
Medulla Oblongata
Respiratory control center, cardiac control center, vasomotor centers
Reticular Formation
Part of the Pons; Arouses the cerebrum to wakefulness, decreases in activity causes sleep, spread throughout the whole brain
Cerebellum
Controls posture, balance and muscle coordination
2 Lateral Ventricles
The largest ventricles (first and second ventricles); Located within the cerebral hemispheres
Third Ventricle
Narrow space that lies on the midline between the lateral masses of the thalamus and hypothalamus
Fourth Ventricle
Located on the midline in the posterior portion of the brain stem just anterior to the cerebellum
Flow of CSF
Lateral ventricles to third ventricle to fourth ventricle to central canal or subarachnoid space
Gray Matter
Internal and butterfly shaped; Central canal-location for CSF
White Matter
Divided into 3 regions; the anterior, posterior, and lateral columns. These columns are bundles of myelinated axons of interneurons that extend up and down the spinal cord
Ascending (Sensory) Tract
TOWARD the brain
Descending (Sensory) Tract
AWAY from the brain
3 Types of Peripheral Nerves
Motor Nerves
Sensory Nerves
Mixed Nerves
Motor Nerves
Contain motor neuron axons
Sensory Nerves
Contain sensory neuron dendrons
Mixed Nerves
Contain axons and dendrons of motor and sensory neurons
Sympathetic NS
"Fight or Flight"
aka Texas Chainsaw Massacre
Parasympathetic NS
"Rest & Digest"
aka couch potato
Afferent
AWAY from stimulus
Efferent
TOWARD extremities
Sensory Neurons
TOWARD CNS
Motor Neurons
FROM CNS to effectors
Olegodendrocyte
Myelinated in CNS
Astrocyte
Forms blood-brain barrier
Microglial
Engulfs bacterial debris
Ependymal
Epithelial-like lining of CNS
CNS Neuralgia
Olegodendrocyte
Astrocyte
Microglial
Ependymal
General Senses
Touch, temperature, pressure and pain
Special Senses
Taste, smell, vision, hearing and equilibrium (balance)
Projection
Allows you to know the origin of the sensation
Adaptation
Decline in the rate of impulse formation due to repeated stimulation by the same stimulus
Free Nerve Endings
Function in touch, itch, temperature and pain
Chemoreceptors
Sensitive to chemicals; on nose and tongue
Mechanoreceptors
Sensitive to sound wave vibrations; in the ear
Photoreceptors
Sensitive to light rays; in the eyes
Tympanic Membrane
Eardrum
Ear Ossicles
Malleus
Incus
Stapes
Equilibrium
Balance
Static Equilibrium
Occurs when the head is motionless
Dynamic Equilibrium
Occurs when the head is moving
Sclera
Opaque, white portion of the eye; Tough, fibrous layer that provides protection for the delicate internal portions of the eye and for the optic nerve
Cornea
The anterior clear window of the eye; It bends light rays as they pass through it
Choroid Coat
Contains blood vessels that nourish the eye
Ciliary Body
Contains the ciliary muscles and forms a ring around the lens just anterior to the choroid coat
Lens
The structure that focuses images on the retina
Suspensory Ligaments
Extends from the ciliary body to the lens, and they hold the lens in place
Iris
The color portion of the eye
Rods
Photoreceptors for black and white vision because they are sensitive only to the presence of light
Cones
Photoreceptors for color vision, but they require bright light and do not function in dim light
Macula
A yellowish disk on the retina directly behind the lens
Fovea Centralis
a small depression in the center of the macula
Optic Disc
The blind spot; the site of retinal nerve fibers that partially cross over to the opposite side
Ciliary Muscles
Contraction and relaxation change the shape of the lens
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