"LARSON'S NOTES"
Study Guide Expanded Notes
for
EXCELSIOR COLLEGE
Anatomy and Physiology
IV. Integration and Regulatory Mechanisms (23%)
A. Nervous system
1. Cell types
a. Neuron: cell body, dendrites, axon, neurofibrils, myelin sheath, nodes of Ranvier, telodendria
(1) Structural classification: unipolar, bipolar, multipolar
(2) Functional classification: afferent (sensory), efferent (motor), association (interneuron)
b. Supportive cells
neuroglia or glia are connecting and supporting cells
(1) CNS: neuroglia or glial cells (astrocytes, oligodendrocytes, microglia, ependymal cells)
Astrocytes, star shaped neuroglia, are the largest and most abundant of the glial cells, are responsible for maintaining blood- brain-barrier through cellular tight junctions, structural support for neurons, and become the scar tissue after damage as well as preforming multiple other functions.
Oligodendrocytes are smaller cells and are responsible for the formation of the myelin sheath around axons in the central nervous system (CNS) which increase the conduction velocity of nerve impulses. These glial cells may be myelinated on several multiple axons.
Microglia are small, usually stationary cells that are phagocytic glial cells which fight microbial invaders and also clean up cellular debris.
Eppendymal cells, which resemble epitheal cells, line the ventricles of the CNS, and produce, secrete and circulate the CSF.
(2) PNS: Schwann cells
Schwann cells are responsible for myelination of the axons in the peripheral nervous system (PNS) which increase the conduction velocity of nerve impulses
Node of Ranvier
Satellite cells are simmilar to the astrocytes but are located in the peripheral nervous system PNS, providing the structural support and nutritional regulation.
2. Nerve impulse: membrane excitation (graded, voltage-regulated potential), ,membrane inhibition, facilitation, saltatory conduction
3. Synapse: excitation (EPSP), inhibition (IPSP), convergence, divergence, calcium modulation, neurotransmitters, MAO, specificity of receptors (adrenergic, cholinergic), fatigue
4. Reflexes (knee jerk, stretch, withdrawal)
5. Development and growth
a. Ectoderm: neural (medullary) [late, neural tube (brain and spinal cord)
b. Brain: forebrain, midbrain, hindbrain
6. Divisions
a. Central nervous system
(1) Brain : gray and white matter
(a) Forebrain (prosencephalon): telencephalon (lateral ventricles, cerebral cortex, basal nuclei, rhinencephalon), diencephalon (third ventricle, epithalamus, thalamus, metathalamus, hypothalamus)
Ventricles: The hollow spaces within the CNS that results from the embryologic neural tube hollow center. The ventricles are are filled with CSF and lined by ependymal cells, some that produce CFS and others with cilia that keep the fluid moving.
(b) Midbrain (mesencephalon): cerebral aqueduct, cerebral peduncles, corpora quadrigemina
(c) Hindbrain (rhombencephalon): forth ventricle, metencephalon (cerebellum, pons), myelencephalon (medulla oblongata)
Arachnoid membrane (human brain), Longitudinal fissure, Lateral sulcus, Cerebral hemispheres, Frontal lobe, Occipital Lobe, Temporal lobe, Parietal lobe, Central sulcus, Occipital notch, Precentral gyrus, Postcentral gyrus, Primary motor cortex, Primary sensory cortex, Olfactory bulb and tract, Optic chiasm, Pons, Cerebellum, Medulla oblongata
(2) Spinal cord: gray and white matter
The white matter of the spinal cord is divided into three columns :
Posterior white column: ascending tracts - sensory - fine touch and limb postion (proprioception) to the brain.
Lateral white column: ascending and decending tracts - both sensory and motor tracts - sensory tracts convey pain, crude touch and pain to the brain - motor tracts convey motor commands to the motor neurons of the voluntary muscles.
Anterior white column: descending tracts - reflex motor commands for posture to the motor neurons.
(a) Ascending tracts (sensory): for example: posterior columns, spinothalamic pathways, spinocerebellar pathways
(b) Descending tracts (motor): for example: pyramidal pathways (corticospinal tracts), extrapyramidal pathways (rubrospinal and reticulospinal)
ventral root nerve, dorsal root nerve, spinal nerves, dorsal root ganglion
Conus medullaris is the conical portion end of the spinal cord at L1 to L2, below which a spinal puncture can be undertake without damaging the cord. Extending from the conus medullaris to the coccygeal is the filum terminale, composed of nonnervous fibrus tissue, mainly pia mater.
Cauda equina is the "horses tail" appearing collection of nerves that flow from the conus medullaris downward in the vertebral canal before exiting.
(3) Meninges: dura mater, arachnoid, pia mater
(4) Cerebrospinal fluid (formation, flow, reabsorption, and function)
b. Peripheral nervous system
whistle
gritteeth
close eyes, tough face
2 ft from ear, rub fingers together
swallow
stick tongue out
shrug shoulders
stand feet together, arms out to sides
examiners finger to pt nose rappid finger movement
stand and ballance on left & right foot
(1) Cranial nerves (12 pairs): name, number, type, function
Cranial nerve I (CNI): Olfactory nerve: sensory:
Cranial nerve II (CNII): Optic nerve:
Cranial nerve III (CNIII): Oculomotor nerve:
Cranial nerve IV (CNIV): Trochlear nerve:
Cranial nerve V (CNV): Trigeminal nerve:
Cranial nerve VI (CNVI): Abducens nerve:
Cranial nerve VII (CNVII): Facial nerve:
Cranial nerve VIII (CNVIII): Vestibulocochlear nerve:
Cranial nerve IX (CNIX): Glossopharyngeal nerve:
Cranial nerve X (CNX): Vagus nerve:
Cranial nerve XI (CNXI): Accessory nerve:
Cranial nerve XII (CNXII): Hypoglossal nerve:
(2) Spinal nerves
(a) Thirty-one pairs (8 cervical, 12 thoractic, 5 lumbar, 5 sacral, 1 coccygeal): dorsal root, ventral root
(b) Plexi: cervical, brachial, lumbar, sacral
c. Autonomic nervous system (visceral efferent system)
(1) Sympathetic division (thoracolumbar)
(2) Parasympathetic division (craniosacral)
(3) Anatomical and functional aspects
(a) Preganglionic (white rami root) and postganglionic (gray rami root) fibers: for example: adrenergics, cholinergics
B. Sensations
1. General senses
a. Exteroceptors: free nerve endings, Pacinian corpuscles, Meissner's corpuscles, Ruffini end organ, Krause end organ
b. Chemoreceptors (carotid and aortic bodies)
c. Baroreceptors (carotid and aortic sinuses)
d. Stretch receptors of the lung (Hering-Breuer reflux)
e. Proprioceptors: muscle spindles, tendon organ, joints
2. Special senses
a. Visual
(1) Anatomy of eye: for example: layers of eyeball, extraocular muscles
(2) Physiology of vision and errors of refraction (CNII)
b. Auditory
(1) Anatomy of ear: for example: layers of eyeball, extraocular muscles
(2) Physiology of hearing (mechanics, organ of Corti) (CNVIII)
c. Olfactory: olfactory nerves, olfactory membrane, conchae (CNI)
d. Gustatory: tongue, taste buds (papillae of tongue), classes of taste (CNXI, XII)
e. Balance and equilibrium
(1) Anatomy of semicircular canals (utricle and saccule)
(2) Physiology of balance (static vs. Dynamic equilibrium) (CNVIII)
C. Endocrine system
1. Hormones
a. Amino acid derivatives
b. Peptide hormones
c. Proteins
d. Steroids
2. Mechanisms of hormonal action: first and second messengers
a. Plasma membrane: adenyl cyclase mechanism, c-AMP
b. Cytosol: nuclear membrane receptor mechanism
3. Endocrine glands: structure and function
a. Pituitary (hypophysis cerebri)
(1) Neurohypophysis (pars nervosa): ADH, oxytocin
(2) Adenohypophysis (pars distalis): ACTH, GH, TSH, FSH, LH (ICSH)
(3) Relationship to hypothalamus (hypothalamic-hypophyseal portal system and tract)
b. Thyroid: thyroxine (T4), triiodothyronine (T3), calcitonin
c. Parathyroid: parathormone (PTH)
d. Adrenal (suprarenal)
(1) Medulla: epinephrine, norepinephrine, relationship to the sympathetic division of the autonomic nervous system
(2) Cortex: glucocorticoids, mineralocorticoids, sex hormones
e. Pancreas: islets of Langerhans, insulin, glucagon
f. Gonads
(1) Ovaries: estrogen and progesterone
(2) Testes: androgens (testosterone)
g. Thymus (role in T4 and T8 synthesis)
h. Pineal gland: melatonin
i. Placenta: estrogens, progesterone, human chorionic gonadotropin (HCG)
4. Other secretory tissue
a. Gastrointestinal mucosa ( enteroendocrine cells): gastrin, secretin, cholecystokinin (CCK)
b. Kidney: for example: renin, erythropoietin
5. Hypothalamus
a. Releasing factors and inhibiting factors
b. Posterior pituitary hormones (ADH, oxytocin)