GENERAL
CHAPTER 4: THE PHYSIOLOGICAL BASIS OF BEHAVIOR
PSYCHOLOGY
diameter of the soma in length. The axon carries nerve
signals away from the nucleus.
THREE MECHANISM OF BEHAVIOR 4. Myelin Sheath: the main purpose of a myelin layer (or
sheath) is to increase the speed at which impulses
propagate along the myelinated fiber
1. THE RECEIVING MECHANISM
5. Axon Terminal / Synaptic Nerve Ending: contains
• Sense Organs are sensitive nerve endings located in certain
synapses, specialized structures where neurotransmitter
body parts.
chemicals are released to communicate with target
• Characteristics of Sense Organs: neurons.
1. Sensitivity and Irritability: power to react to stimulus.
• Types of Neurons according to basis function:
2. Conductivity: power to conduct and transport nerve
1. Sensory Neurons (Afferent Fibers): conduct impulses
impulses.
towards the brain / nervous system.
3. Specificity: attribute of reacting to a particular stimulus.
2. Association Neurons: connecting conduct impulses
4. Adaptability: power to become used to particular
within the nervous system.
stimulus.
3. Motor Neurons (Efferent Fibers): conduct impulses
• Types of Sense Organs according to location: away from the brain/ nervous system.
1. Exteroceptors: found in the eyes, ears, nose, mouth,
skin and are sensitive to external stimulus. Division of Human Nervous System
I. Autonomic Nervous System
Sympathetic – flight or aggression response  release of
norepinephrine  increase in all bodily activity except GI
(constipation); adrenergic; parasympatholytic response.
REMEMBER: GIT is the least important area during stress 
decreased blood flow in the area; Increased blood flow in the brain,
heart and skeletal muscles
 Dry mouth
 Increase in HR and BP
 Tachypnea
 Constipation
2. Interoceptors: sense organs in the respiratory tract,
digestive and genitor-urinary tract. Parasympathetic – flight or withdrawal response  release of
Acetylcholine  decrease in all bodily activity except GI (diarrhea);
3. Proprieoceptors: sense organs embedded in muscles, chonlinergic/ vagal/ sympatholytic response
tendons and joints.
 Increased salivation
2. THE CONNECTING MECHANISM  Decreased HR and BP
 Decresead RR
• Neurons: is an electrically excitable cell that processes and  Diarrhea
transmits information by electrical and chemical signaling.  Seizures
The basic conducting unit of nervous system.
II. Central Nervous System (BRAIN)
• Basic Part of a Neuron
1. Nucleus: responsible for protein synthesis or  CEREBRUM – divided into two hemispheres, the left and
manufacturing chemical substances for neuron right and is bridged by the corpus callosum
nourishment.  Motor, sensory, integrative function
 Lobes:
2. Dendrites: of a neuron are cellular extensions with
 Frontal – controls higher cortical thinking,
many branches, and metaphorically this overall shape personality development, motor activity, contains
and structure is referred to as a dendritic tree. This is BROCA’s are or the motor-speech center.
where the majority of input to the neuron occurs. (Expressive Aphasia)
3. Axon: is a finer, cable-like projection that can extend  Occipital – vision
tens, hundreds, or even tens of thousands of times the
Prepared by: Mark Fredderick R. Abejo RN,MAN 1

GENERAL
CHAPTER 4: THE PHYSIOLOGICAL BASIS OF BEHAVIOR
PSYCHOLOGY
 Parietal – appreciation and discrimination of
sensory impulses (pain, touch, pressure, heat and
cold) II. Optic Vision
 Temporal – hearing, short term memory, III. Oculomotor Eye
contains the general interpretative area— Movement
Wernicke’s aphasia
 Insula (Island of Reil) – visceral function IV. Trochlear (smallest) (“down”) Eye
(internal area) Movement
 Limbic System (Rhinencephalon) – sense of
smell, libido or sexual urge control, long term V. Trigeminal (largest) Chewing
memory
VI. Abducens (“at the sides”) Eye
Movement
VII. Facial Facial
Expression
VIII Acoustic (Vestibulocochlear) Hearing and
. Balance
IX. Glossopharyngeal Taste
X. Vagus (longest) Gag Reflex
and control
the muscle of
the throat
XI. Accessory Shoulder
Movement
XII. Hypoglossal Tongue
 MIDBRAIN – acts as a relay station for sight and hearing Movement
particularly helps in size and reaction of pupils and hearing
acuity
 DIENCEPHALON (Interbrain) B. Spinal Nerves
 Thalamus – acts as a relay station for sensation
 Hypothalamus – controls temperature, BP, sleep and
wakefulness, thirst, appetite (satiety), some emotional
responses like fear, anxiety and excitement, controls
pituitary functions
 BRAIN STEM
 Pons – controls rate, rhythm and depth of respiration
 Medulla Oblongata – lowest part; damage: most life
threatening; controls respiration, HR, swallowing,
vomiting, hiccups, vasomotor center
 CEREBELLUM – smallest part; “lesser brain”; balance,
equilibrium, gait and posture.
III. Peripheral Nervous System
A. Cranial Nerves
31 Spinal Nerves
 Cervical – 8 pairs
 Thoracic – 12 pairs
 Lumbar – 5 pairs
 Sacral – 5 pairs
 Coccygeal – 1 pair
3. THE REACTING MECHANISM (Muscles and Endocrine
Glands)
12 CRANIAL NERVE
A. Muscles
I. Olfactory Smell • The Kinds of Muscles
Prepared by: Mark Fredderick R. Abejo RN,MAN 2

GENERAL
CHAPTER 4: THE PHYSIOLOGICAL BASIS OF BEHAVIOR
PSYCHOLOGY
1. Voluntary Muscles : stripes, skeletal Thymus • Thymosin Stimulates the
2. Involuntary Muscles: visceral, smooth development of T
3. Cardiac muscles lymphocytes.
Adrenal Adrenal Cortex
• Mineralocorticoids Regulates mineral
(Aldosterone / Renin) composition of body fluids
• Glucocorticoids (Cortisol/ Promotes conversion of
Cortisone) protein into sugar.
• Sex Hormones Promotes development of
( Estrogen / Androgen) secondary sex
characteristics
Adrenal Medulla
• Adrenaline / Epinephrine Stimulates heartbeat,
• Characteristics of Muscles inhibits GIT activity,
1. Contractility: power to shorten increase blood flow.
2. Tonicity: power to be in partial contraction • Noradrenalin / Acts to constrict blood
Norepinephrine vessel throughout the
3. Extensibility: power of muscle to stretch
body.
4. Elasticity: power to resume to its original shape
Pancreas Alpha Cell
• Glucagon Raise the blood sugar level
• Functions of Muscles Beta Cell
1. To lend shape to the body. • Insulin Lowers the blood sugar
2. To propel food and waste product along the intestinal level
tract. Delta Cell
3. For movement • Somatostatin Inhibits growth hormone
4. To control blood flow
Gonads Male Testicle Influences the
5. To covert mechanical energy into chemical work
• Testosterone development of secondary
6. To generate heat sexual characteristics
Sperm production
B. Endocrine Glands
Female Ovaries Influences the
• Estrogen development of secondary
sexual characteristics
• Progesterone Maintenance of
pregnancy.
Glands Hormones Functions
Pituitary Anterior Pituitary
• Growth Hormones Stimulates growth
• Thyroid Stimulating H. Stimulates thyroid gland
• Adrecocorticotropic H. Stimulates adrenal gland
• Follicle Stimulating H. Ripening of follicles
(female)
• Luteinizing H. Sperm production (male)
• Prolactin Stimulates ovulation
Milk Production
Posterion Pituitary
• Oxytocin
• Antidiuretic H. Stimulates contraction
Regulates volume of urine
Thyroid • Thyroxin Regulates metabolism
• Calcitonin Regulates calcium by bone
re-absorption
Parathyroid • Parathormone Regulates calcium by bone REFERENCES:
demineralization.
Prepared by: Mark Fredderick R. Abejo RN,MAN 3

GENERAL
CHAPTER 4: THE PHYSIOLOGICAL BASIS OF BEHAVIOR
PSYCHOLOGY
1. Kahayon and Aquino, General Psychology 4th edition
2. Gaerlan, Limpingco and Tria, General Psychology 5th edition
3. Plotnik, Introduction to Psychology 3rd edition
Prepared by: Mark Fredderick R. Abejo RN,MAN 4