TIS
Chapter 5
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Forebrain |
I. INTRODUCTION
-- diencephalon: 2nd division of forebrain
1. Epithalamus:
2. Thalamus:
3. Hypothalamus:
4. Third Ventricle:
5. Part of the Pituitary Gland:
II. THIRD VENTRICLE
-- hypothalamus, thalamus, and epithalamus form its floor, walls and roof
III. EPITHALAMUS
A. Pineal Gland (Pineal Body): appears to regulate the body's clock
* produces melotonin
IV. THALAMUS
-- two oval masses of gray matter, covered w/white matter
-- Major function: relay point and processing center for all sensory impulses (except smell) running to cerebral cortex
V. HYPOTHALAMUS
-- Major function: serves as center for controlling autonomic (visceral, involuntary) activity and endocrine (hormonal) activity
-- specific functions:
1. Cardiovascular regulation:
2. Temperature Regulation:
3. Water and Electrolyte Balance:
* electrolyte: ions and molecules that carry an electric current
* ion: an atom that has a net positive or net negative charge
4. Hunger/Food Intake:
* consists of two centers:
a) hunger center
b) satiety center
5. Sleep-Wake Cycle:
6. Sexual Response:
* "sexual center"
7. Emotional Expression:
* feelings of emotion are expressed as visible physiological and physical changes
8. Endocrine Control:
* produces two hormones which are secreted by the posterior pituitary
* also produces hormones that regulate hormonal secretion of the anterior pituitary
VI. PITUITARY GLAND (HYPOPHYSIS)
-- hangs underneath the hypothalamus
* it is connected by the infundibulum
-- consists of two lobes:
1) adenohypophysis or anterior pituitary
* glandular epithelium
* synthesizes hormones
2) neurohypophysis or posterior pituitary
* axons from neuron cell bodies found in hypothalamus (neurosecretory cells)
I. INTRODUCTION
-- forebrain has two subdivisions:
1. diencephalon:
2. telencephalon: the cerebrum
* concerned w/higher brain fcts.
II. TELENCEPHALON
-- outer gray matter (cortex) and an inner white matter
-- Structure:
1. two cerebral hemispheres
2. hemispheres separated by a longitudinal fissure
3. connection between hemispheres: the corpus callosum
4. Cortex is highly convoluted
* raised area/elevation=gyrus
* depression or groove=sulcus
-- Lobes - 5 pairs:
1. Frontal:
* ends at the central sulcus
A. Broca's area: on left frontal
** motor functions involved w/speech
B. Precentral gyrus:
** primary motor area
** controls voluntary skeletal muscle movement
2. Parietal:
* ends anteriorly at central sulcus
* laterally ends at lateral sulcus
A. Postcentral gyrus:
** primary sensory area
B. Speech Comprehension Area("Wernicke's area")
3. Temporal:
* primary auditory area
* memories of auditory and visual experiences stored here
4. Occipital:
* receives/assembles visual info
* coordinates focusing of eyes
5. Insula: deep to the lateral sulcus
* memory
-- Basal Ganglia: paired masses of gray matter deep in cerebrum
III. RECEPTORS
-- Def: receptor = specialized dendritic ending of a sensory neuron. Converts a sensory stimulus to a nerve impulse.
-- 3 kinds, based on location:
1. Exteroceptors: near surface of body
* stimuli from outside environment
* ex: cutaneous receptors
* ex: special senses (sight, smell, taste, hearing, balance)
2. Visceroceptors: (enteroceptors)
* stretch receptors in smooth muscle of blood vessels and viscera
3. Proprioceptors: provides info about muscles, joints and tendons
IV. SPECIAL SENSES
A. Olfaction (smell):
* chemoreceptor (sense chemical stimuli)
* bipolar neurons make up olfactory epithelium in superior nasal cavity - they synapse w/ neurons in olfactory bulb
* odorant molecules must first be dissolved in fluid (mucus) before sense of smell can be stimulated
B. Gustation (taste):
* also a chemoreceptor: molecules must be dissolved in saliva
* specialized cells form taste buds
* taste buds are located on fungiform and circumvallate papillae, on tongue
