1. CHAPTER 3
The Physiological
Basis of Behavior

2. The Nervous system-
-is the complex arrangement
throughout the body of highly
specialized cells, the neurons,
which acts as a communication
system, enabling the organism
to respond to external and
internal stimuli.

3.  Senseorgans are sensitive nerve endings
located in certain body parts. Its attributes
are:
 A.) Sensitivity and Irritability: The Power to react
to stimulus
 B.) Conductivity: The power to conduct nerve
impulses
 C.) Specificity: the attribute of reacting to
particular stimulus
 D.) Adaptability: the power to become used to a
particular stimulus.

4.  A.)Extroceptors-found in the eyes,
ears, nose, mouth, skin and are
sensitive to external stimulus.
 B.) Interoceptors- sense organs in
the respiratory tract, digestive and
genito-urinary tract.
 C.) Proprieoceptors- are embeded
in muscles, tendons and joints.

5.  A.Muscles of three kinds:
 Voluntary
 Involuntary
 Cardiac or heart

6. Voluntary Muscles
Voluntary muscles:
Muscles that move and work
when we want them to
Examples:
Arm muscles
Leg muscles
Neck muscles

7. Involuntary Muscles
Involuntary muscles:
Muscles that keep working
whether we think about them
or not
Examples:
Stomach
Lungs
Muscles in the
heart
The Nervous system along with other chemicals in the
body controls our involuntary muscles

8.  Attached to bones by strong fibers called
tendons
 Muscles work in pairs to move the
bones:
Example: biceps (relaxes and
stretches) and triceps (contract and
pull up the elbow)
 Muscle is long, round, and cross
striped

9.  Can be found only in
the HEART
 Muscle contracts and relaxes
about 70 times a minute without
stopping or getting tired
 Muscle is strained both
crossways and longways

10.  Found in many different
organs throughout the body
Examples: esophagus,
stomach, and intestines
 Muscle is slender and
smooth without cross stripes.

11. Fun Facts
The main purpose of the Muscular System is for all
the muscles to work together to create movement!
Muscles make up almost 50% of our body weight
There are more than 600 muscles in the human body

12. Contractility-power of muscles to
shorten.
Tonicity- power to be in partial
contraction.
Extensibility-power to stretch
Elasticity-power to resume to its
original shape.

13.  Functions
 1. To lend shape to the body as the skeletal
or voluntary muscles of the arms and legs do
 2. To propel food and waste product along
the intestinal pathway as smooth muscles in
the digestive tract do
 3. For movement as when the arms and legs
move or when we move the mouth to form the
sounds of speech
 4. To control the flow of blood, automatically
opening and closing the blood vessels in response
to body needs.
 5. To convert mechanical energy to
mechanical work

14.  B.Glands- are special secreting organs which pour
their secretions either directly or indirectly to
the bloodstream.
-have ducts or canals thru which they pour out their
secretions. These includes lachrymal(tear) glands,
sebaceous (sweat);salivary, gastric, sex and
mammary glands.

17.  Pituitary gland is located beneath hypothalamus

18.  Stores
& releases 2 hormones Hypothalamus
produced in hypothalamus:
 Antidiuretic hormone
(ADH/vasopressin) which Neurosecretory
cells of the Axon
promotes H20 conservation by hypothalamus
kidneys
 Oxytocin which stimulates Posterior
pituitary
contractions of uterus during Anterior
pituitary
parturition & contractions of
mammary gland alveoli for
milk-ejection reflex HORMONE ADH Oxytocin
TARGET Kidney tubules Mammary glands,
uterine muscles

19.  Secretes 6
trophic
hormones that
maintain size
of targets
 High blood
levels cause
target to
hypertrophy
 Low levels
cause
atrophy

20.  Growth hormone
(GH) promotes
growth, protein
synthesis, &
movement of amino
acids into cells
 Thyroid stimulating
hormone (TSH)
stimulates thyroid
to produce &
secrete T4 & T3
 Adrenocorticotroph
ic hormone (ACTH)
stimulates adrenal
cortex to secrete
cortisol,
aldosterone

21.  Follicle stimulating
hormone (FSH)
stimulates growth
of ovarian follicles
& sperm production
 Luteinizing
hormone (LH)
causes ovulation &
secretion of
testosterone in
testes
 Prolactin (PRL)
stimulates milk
production by
mammary glands

22.  Other hormones/products of the pituitary
gland include:
 MSH - influences skin pigmentation in some
vertebrates and fat metabolism in mammals
 Endorphins - inhibit the sensation of pain

23.  Releasing & inhibiting
hormones from
hypothalamus are
released from axon
endings into capillary
bed in median eminence
 Carried by hypothalamo-
hypophyseal portal
system directly to
another capillary bed in
A. Pit.
 Diffuse into A. Pit. &
regulate secretion of its
hormones

24. Target glands
produce
hormones that
feedback to
regulate the
anterior
pituitary and
the
hypothalamus

25.  Hypothalamus receives input from higher brain
centers that can affect Pituitary secretion
 E.g. psychological stress affects circadian rhythms,
menstrual cycle, & adrenal hormones

27.  Siton top of
kidneys
 outer cortex
 inner medulla

28.  Adrenal Cortex
 Mineralocorticoids
 Aldosterone which stimulate kidneys to reabsorb Na+ and
secrete K
 Glucocorticoids
 Cortisol which inhibits glucose utilization & stimulates
gluconeogenesis. Inhibits inflammation, Supresses the
immune system

29.  Secretes Epinephrine and Norepinephrine
 "fight or flight" response
 causes:
 Increased respiratory rate
 Increased HR & cardiac output
 General vasoconstriction which increases venous return
 Glycogenolysis & lipolysis
 Etc, etc, etc

30.  Cushing’s disease
 Hyperadrenocorticism
 widened face with acne and flushing
 fatty deposits over back of neck
 stretch marks, easy bruising, hair overgrowth
 diabetes mellitus
 muscle loss and fatigue
 depression and psychosis
 moon-like face,
 Addison’s disease
 Hypoadrenocorticism
 Hyperpigmentation, weight loss

32.  Islocated just below
the larynx
 Secretes T4 & T3 which
set BMR & are needed
for growth,
development
 Also secretes Calcitonin
which lowers blood
calcium levels

33.  Hypothyroidism
 People with inadequate T4 & T3 levels are
hypothyroid
 Have low BMR, weight gain, lethargy, cold
intolerance
 Hyperthyroidism
 Autoimmune disease where antibodies act
like TSH & stimulate thyroid gland to grow
& oversecrete = hyperthyroidism
 Characterized by exopthalmos, weight
loss, heat intolerance, irritability/anxiety,
high BMR, rapid heart rate

34.  Graves disease is
a form of
hyperthyroidism
that often
presents with
exopthalmos

36.  On the
surface of
thyroid gland
 Secrete
Parathyroid
hormone
(PTH)
 Elevates
blood Ca2+
levels

37.  Two
antagonistic
Calcitonin
Thyroid gland
releases
calcitonin.
hormones, Reduces
Stimulates Ca2+ uptake
parathyroid Ca2+ deposition
in bones
in kidneys
hormone (PTH)
and calcitonin STIMULUS: Blood Ca2+
play the major
Rising blood level declines
Ca2+ level to set point
role in calcium Homeostasis:
(Ca2+)
Blood Ca2+ level
(about 10 mg/100 mL)
homeostasis in Blood Ca2+
level rises
STIMULUS:
Falling blood
Ca2+ level
to set point
mammals Stimulates
Ca2+ release
Parathyroid
gland
from bones
PTH
Increases
Ca2+ uptake
in intestines
Stimulates Ca2+
Active
uptake in kidneys
vitamin D

39.  Glugaconraises blood sugar (a cells) Insulin secreted
Which lowers blood sugar (b cells)

40.  Diabetes mellitus is the best-known endocrine
disorder
 Is caused by a deficiency of insulin or a decreased
response to insulin in target tissues
 Is marked by elevated blood glucose levels
 Type I diabetes mellitus (insulin-dependent
diabetes)
 Is an autoimmune disorder in which the immune
system destroys the beta cells of the pancreas
 Type II diabetes mellitus (non-insulin-dependent
diabetes)
 Is characterized either by a deficiency of insulin
or, more commonly, by reduced responsiveness
of target cells due to some change in insulin
receptors

41.  Alphassecrete glucagon in response to low blood
glucose during periods of fasting
 Stimulates glycogenolysis & lipolysis
 Increases blood glucose

42.  Gonads (testes & ovaries) secrete steroid hormones
 The testes primarily synthesize androgens, the main
one being testosterone
 Which stimulate the development and maintenance of the
male reproductive system
 Estrogens, the most important of which is estradiol
 Are responsible for the maintenance of the female
reproductive system and the development of female
secondary sex characteristics
 Progestins, which include progesterone
 Are primarily involved in preparing and maintaining the
uterus in mammals

43.  Testosterone causes an increase in muscle and bone
mass and is often taken as a supplement to cause
muscle growth

45.  Placenta
secretes
estrogen,
progesterone,
hCG which
maintains
pregnancy,prev
ents eggs from
ripening in the
ovary, and
numerous
polypeptide
hormones

46.  A.The Neuron is the basic
conducting unit of the nervous
system. It has 3 principal parts:
Dendrites-are specialized signal-
receiving structures where the
impulse (input)enters ; the cell body
(central region) which integrates
input and output and the axon
where the output is discharged.

47.  According to speed
 According to basic function
a. Sensory Neurons (afferent fibers)
-conduct impulses to the nervous system.
b. Association Neurons
-central and connecting conduct impulses
with in the nervous system.
c. Motor Neurons (efferent fibers)
-conduct impulses away from the nervous
system

50. The skull is a rounded layer of
bone designed to protect the brain
from penetrating injuries.

51. The base of the skull is
Bony ridges
rough, with many bony
protuberances.
These ridges can result in
injury to the temporal lobe
of the brain during rapid
acceleration.
Injury from contact
with skull

52. The brain requires a rich
blood supply, and the
space between the skull
and cerebrum contains
many blood vessels.
These blood vessels can
be ruptured during
trauma, resulting in
bleeding.
Groove for middle
meningeal artery

53. The human brain
requires a constant
supply of oxygen. A
lack of oxygen of just
a few minutes results
in irreversible damage
to the brain.

54. Dendrites:
Collects information
from other neurons.
Cell Body
Axon:
Transmits information
to other neurons.
Click image to play or pause video

55. The meninges are layers
of tissue that separate the
skull and the brain.
Skull
Dura mater
Arachnoid Layer
Pia Mater
Brain

57. The largest portion of the brain
is the cerebrum. It consists of
two hemispheres that are
connected together at the
corpus callosum. Corpus callosum
The cerebrum is often divided
into five lobes that are
responsible for different brain
functions.

58. Neocortex
The cerebrum’s surface—the
neocortex—is convoluted into
hundreds of folds.
The neocortex is where all the
higher brain functions take place.

59. The cerebral cortex is a thin layer of cells about 1.5 to
4 mm thick.
The cortex provides the connections and pathways
for the highest cognitive functions, such as language
and abstract thinking.
The cerebral cortex contains about 25 billion neurons,
more than 62,000 miles of axons, and
300,000,000,000,000 synapses.
Neocortex layer
The thin layer of the
neocortex is dense
with neurons.

60. Limbic Lobe
Frontal Lobe
Parietal Lobe
Occipital Lobe
Temporal Lobe

61. The frontal lobe is the area of
the brain responsible for
higher cognitive functions.
These include:
• Problem solving
• Spontaneity
• Memory
• Language
• Motivation
• Judgment
• Impulse control
• Social and sexual behavior.

62. The temporal lobe plays a
role in emotions, and is
also responsible for
smelling, tasting,
perception, memory,
understanding music,
aggressiveness, and
sexual behavior.
The temporal lobe also
contains the language
area of the brain.

63. The parietal lobe plays a
role in our sensations of
touch, smell, and taste. It
also processes sensory
and spatial awareness,
and is a key component
in eye-hand co-ordination
and arm movement.
The parietal lobe also
contains a specialized
area called Wernicke’s
area that is responsible
for matching written
words with the sound of
spoken speech.

64. The occipital
lobe is at the
rear of the
brain and
controls vision
and
recognition.

65. The limbic lobe
is located deep
in the brain,
and makes up
the limbic
system.

66. The limbic system is the
area of the brain that
regulates emotion and
memory. It directly
connects the lower and
higher brain functions.
A. Cingulate gyrus
B. Fornix
C. Anterior thalamic
nuclei
D. Hypothalamus
E. Amygdaloid nucleus
F. Hippocampus

67. The cerebellum is connected to the
brainstem, and is the center for
body movement and balance.

68. Thalamus means “inner room” in Greek,
as it sits deep in the brain at the top of
the brainstem.
The thalamus is called the gateway to
the cerebral cortex, as nearly all
sensory inputs pass through it to the
higher levels of the brain.

69. The hypothalamus sits under the thalamus at
the top of the brainstem. Although the
hypothalamus is small, it controls many critical
bodily functions:
• Controls autonomic nervous system
• Center for emotional response and behavior
• Regulates body temperature
• Regulates food intake
• Regulates water balance and thirst
The hypothalamus is
• Controls sleep-wake cycles shaded blue. The pituitary
• Controls endocrine system gland extends from the
hypothalamus.

70. The medulla oblongata merges
seamlessly with the spinal cord and
creates the base of the brainstem.
The medulla is primarily a control
center for vital involuntary reflexes
such as swallowing, vomiting,
sneezing, coughing, and regulation of
cardiovascular and respiratory activity.
The medulla is also the origin of many
cranial nerves.

71. The pons is the rounded
brainstem region between the
midbrain and the medulla
oblongata. In fact, pons means
“bridge” in Latin.
The main function of the pons is
to connect the cerebellum to the
rest of the brain and to modify the
respiratory output of the medulla.
The pons is the origin of several
cranial nerves.

72. The ventricles are a complex
series of spaces and tunnels
through the center of the brain.
The ventricles secrete
cerebrospinal fluid, which
suspends the brain in the skull.
The ventricles also provide a
route for chemical messengers
that are widely distributed through
the central nervous system.
Click image to play or pause video

73. Cerebrospinal fluid is a colorless
liquid that bathes the brain and spine.
It is formed within the ventricles of the
brain, and it circulates throughout the
central nervous system.
Cerebrospinal fluid fills the ventricles
and meninges, allowing the brain to
“float” within the skull.
Click image to play or pause video

74. The brainstem is the most
primitive part of the brain and
controls the basic functions of
life: breathing, heart rate,
swallowing, reflexes to sight or
sound, sweating, blood
pressure, sleep, and balance.
The brainstem can be divided Click image to play or pause video
into three major sections.
Detailed brainstem anatomy.

75. Front
More Information: Rear
Medulla
Thalamus
Pons

76. Midbrain
Pons
Medulla Oblongata

77. I. Olfactory nerve
II. Optic nerve
III. Oculomotor nerve
IV. Trochlear nerve
V. Trigeminal nerve
VI. Abducens nerve
VII. Facial nerve
VIII. Vestibulocochlear nerve
IX. Glossopharyngeal nerve
X. Vagus nerve
XI. Accessory nerve
XII. Hypoglossal nerve

78. • Vision
• Taste
• Cognition
• Emotion
• Speech
• Language
• Hearing
• Motor Cortex
• Sensory Cortex
• Autonomic Functions

79. The visual cortex
resides in the occipital
lobe of the brain.
Sensory impulses
travel from the eyes via
the optic nerve to the
visual cortex.
Damage to the visual
cortex can result in
blindness.

80. The gustatory complex
(green circle) is the part
of the sensory cortex
(purple area) that is
responsible for taste.

81. The prefrontal cortex is
involved with intellect,
complex learning, and
personality.
Injuries to the front lobe
can cause mental and
personality changes.

82. Prefrontal cortex
Emotions are an extremely
complex brain function. The
emotional core of the brain is the
limbic system. This is where
senses and awareness are first
processed in the brain.
Mood and personality are
mediated through the prefrontal
cortex. This part of the brain is
the center of higher cognitive and
emotional functions. Limbic system

83. Broca’s Area
Broca’s area is where we
formulate speech and the
area of the brain that sends
motor instructions to the
motor cortex.
Injury to Broca’s area can
cause difficulty in speaking.
The individual may know
what words he or she wishes
to speak, but will be unable
to do so.

84. Auditory Association Area
Wernicke’s area is a
specialized portion of the
parietal lobe that recognizes
and understands written and
spoken language.
Wernicke’s area surrounds the
auditory association area.
Damage to this part of the
brain can result in someone
hearing speech, but not
understanding it. Wernicke’s Area

85. There are two auditory
areas of the brain:
• The primary auditory
area (brown circle) is what
detects sounds that are
transmitted from the ear. It
is located in the sensory
cortex.
• The auditory association
area (purple circle) is the
part of the brain that is
used to recognize the
sounds as speech, music,
or noise.

86. The motor portion of the
cerebrum is illustrated here. The
light red area is the premotor
cortex, which is responsible for
repetitive motions of learned
motor skills. The dark red area is
the primary motor area, and is
responsible for control of
skeletal muscles.
Different areas of the brain are
associated with different parts of
the body.
Injury to the motor cortex can
result in motor disturbance in the
associated body part.

87. The sensory portion of the
cerebrum is illustrated here.
Different areas of the brain are
associated with different parts of
the body, as can be seen below.
Injury to the sensory cortex can
result in sensory disturbance in
the associated body part.

88. The brainstem controls
the basic functions of life.
Damage to these areas
of the brain are usually
fatal:
•The pons plays a critical Pons
role in respiration. Medulla Oblongata
•The medulla oblongata
is responsible for
respiration and
cardiovascular functions.