Bio 102: Fundamentals in Animal Biology. The Nervous System.

1. INTEGRATION AND
CONTROL
• The nervous and endocrine systems interact to control most of
the body functions
• The nervous system exerts rapid controls via nerve impulses; the
endocrine system’s effects are mediated by hormones and are
more prolonged.
• Both systems are communication systems that receive and
deliver messages throughout the body.

2. The Nervous
System

3. Integration and Control
• The nervous system control most of the
body functions
• This exerts rapid controls via nerve
impulses
• are communication systems that
receive and deliver messages
throughout the body.
• The nervous system allows reaction to
a stimulus 3

4. • The nervous system allows reaction to a
stimulus.
−A stimulus is a change in the
environment that elicit a response
• Example: A hot stove
• The reactions are automatic.
−no need to think about the reactions
• Example: If a bug flies by the eye,
automatically the eye will blink
4

5. The Nervous System
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6. THREE (3) FUNCTIONS OF NERVOUS SYSTEM
3. Generates Motor Output
- motor output is the
conduction of signals from
the integration center, to the
effector cells, the muscle
cells or gland cells that
actually carry out the body´s
responses to the stimuli
2. Performs Integration
- processes and interprets
sensory input and decides
what should be done at
each moment
1. Receives Sensory Input
- uses millions of sensory
receptors (present in skin
and other organs )to
monitor changes occurring
both inside and outside of
the body Sensory input
Motor output
Integration
6

7. 7
Basic structure of a nerve cell
• Neuron/Nerve cell - The functional unit of the
nervous system
• Cell body – integrates the message
• Dendrites - are highly branched extensions
that receive signals from other neurons and
convey this information toward the cell body
• Axon - typically a much longer extension that
transmits signals to other cells
• The myelin sheath, resembles a chain of
oblong beads, wraps around the axon
• Gaps between Schwann cells are called nodes
of Ranvier
• A typical axon has hundreds or thousands of
these branches, each with a synaptic terminal
at the very end.
• The junction between a synaptic terminal and
another cell is called a synapse.

8. Types of neurons
8
Sensory neuron – transmit signals/nerve impulses from the afferent or sensory organs of the
brain (sense)
- Sensory (afferent) neurons take nerve impulses from sensory receptors to the CNS
Motor neuron - take nerve impulses from the CNS to muscles or glands
Interneurons - Occur entirely within the CNS. convey nerve impulses between various parts of
the CNS. some take messages from one side of the spinal cord to the other or from the brain to
the cord, and vice versa

9. NERVE SIGNALS AND THEIR TRANSMISSION
• Membrane Potential – potential energy
exists as an electrical charge difference
across the neuron’s plasma membrane
• The potential of a neuron that is not
being stimulated is its resting potential
• A resting membrane has many open
potassium (K+) channels but only a few
open sodium (Na+) channels, allowing
much more potassium than sodium to
diffuse across the membrane.
• Therefore, Na+ is more concentrated
outside the neuron than inside.
• Sodium-potassium (Na+-K+) pumps –
membrane proteins that help maintain
resting potential
Nerve function depends on charge
differences across neuron membranes

10. • Action potential - a change in membrane voltage that transmits a nerve
signal along an axon.
• It is caused by the opening and closing of channel proteins with gates
that open at a particular voltage or membrane potential
A nerve signal begins as a change in the membrane potential

11. 1. When this region of the axon
(blue) has its Na+ channels open,
Na+ rushes inward, and an
action potential is generated
2. Soon, the K+ channels in that
same region open, allowing K+
to diffuse out of the axon; at this
time, its Na+ channels are closed
and inactivated at that point on
the axon
3. A short time later, we would see
no signs of an action potential at
this (far-left) spot because the
axon membrane here has
restored itself and returned to
its resting potential
Propagation of the action potential
along an axon

12. 12
Chemical synapse
- The communication
point between two
neurons, or between a
neuron and a muscle or
gland

13. Nervous system of representative
organisms
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14. Comparative functional anatomy of nervous system in invertebrates
Protozoa
- Protozoans lack specialized nervous
system to respond to the environment.
-Single cell function as both the receptor and
the effector.
-Contain an eyespot that act as a light
sensitive receptor.

15. Comparative functional anatomy of nervous system in invertebrates
Porifera
-Poriferans or the sponges are the
only multicellular animals without a nervous
system. They do not show any neurons or
sensory cells.
-Although they lack a nervous system
they are sensitive to pressure and touch that
helps in their locomotion.

16. Comparative functional anatomy of nervous system in invertebrates
Cnidaria
-Contains a diffuse nerve net.
-Sensory neurons, intermediate
neurons and motor neurons are present
-These neurons are connected
together by synapses.
-Synapses carry impulses to both
directions within the nerve net.
Hydra sp.
Nerve net is present.
Contain multipolar neurons.

17. Echinodermata
-Echinoderms show ganglia along the
radial nerves.
-They include the cell bodies of
almost all motor neurons and
intermediate neurons.
-A central nerve ring surrounds the
gut connecting the radial nerves.
-Some shows Ocelli to sense light.
- Sensory neurons lie within the
ectoderm, and send axons to the radial
nerves.
Comparative functional anatomy of nervous system in invertebrates

18. Comparative functional anatomy of nervous system in invertebrates
Platyhelminthes
- Bilateral symmetry and cephalization have led to the nervous system.
- Shows the primitive arrangement of the central nervous system.
- Nervous system resembles a ladder.
- Two long nerves are connected to the cerebral ganglia
located in the head region.
- Short, smaller nerves are connected to the nerve cord.
- Auricles can be found at the sides of the head.
- These contain sensory receptors.
- Eyespots are also present.
Turbellaria (Planarians)
Cestoda (Tapeworms)

19. Nematoda
- At the anterior end cerebral ganglion is present
composed of dense circular nerve ring surrounding the
pharynx.
- Arising from the nerve ring four nerves run along the
length of the body as one dorsal, one ventral and two lateral
nerves.
- Each nerve is located within a cord of connective tissue
lying beneath the cuticle and between muscle cells.
- Dorsal nerve trunk is motor, lateral trunks are sensory
and ventral nerve function as both.
Comparative functional anatomy of nervous system in invertebrates

20. Annelida
- Nervous system is segmented.
- Pair of cerebral ganglia (supra-pharyngeal)
situated above and in front the pharynx.
- Two lateral nerves (circum or pharyngeal
connectives) form a ring around the pharynx connecting
the ganglia.
- A pair of mid ventrally placed nerves that
connected to the anterior nerve ring, run throughout the
length of the body. These nerves have a ganglion in
each of the body segment from which nerves are given
out to various organs.
- Most annelids have giant axons.
- Some annelids have ocelli or simple eyes.
Comparative functional anatomy of nervous system in invertebrates

21. Mollusca
-Shows great range of nervous systems.
-Typical nervous system of Mollusks is
composed of three pairs of ganglia connected
with one another by bundles of nerve fibers but
distributed in a characteristically scattered
manner.
- One pair of ganglia above the oesophagus
is called as "supra-oesophageal" or "cerebral"
ganglion.
- A pair of ganglia below the oesophagus is
called as "infra-oesophageal" or "pedal"
ganglion.
- The other pair of ganglia is called as
"branchial" or "parieto-splanchnic" ganglion.
- In higher Molluscs, the cerebral and pedal
ganglia are fused forming an oesophageal ring.
- Several ganglia are present that are
connected with long nerves.
Comparative functional anatomy of nervous system in invertebrates

22. Arthropoda
-Similar to annelid nervous system
but more advanced in structure.
-Central nervous system is present.
-Supra-oesophageal or cerebral
ganglion is located in the head
segment. This serves as the brain.
-Most arthropods show well
developed sensory organs such as
compound eyes and antennae.
-Compound eyes contain
‘Ommatidia’ that samples a small
part of the visual field.
Comparative functional anatomy of nervous system in invertebrates

23. • Peripheral
Nerves
WHAT PARTS DO YOU
KNOW THAT ARE IN
THE NERVOUS
SYSTEM?
•Brain
• Spinal Cord
Vertebrate Nervous System

24. Stages in the processing of information by
Nervous System
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25. Divisions of the Nervous System
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26. 27

27. 28
Divisions of the nervous system
A. Central nervous system
A. Includes the brain and spinal cord
• Seat of complex brain functions such as
memory, intelligence, learning and emotion
(love, hate, fear, anger, elation and
sadness)
• Receives and interprets the countless
signals that are sent to it from other parts
of the body and from the external
environment

28. • The brain controls
everything in the
body
• The human brain is
about 1.3kg of jelly-
like tissue made up
of ca. 100B neurons
• divided into three
parts and is
protected by the
skull or cranium
29

29. 1) Dura matter- outermost
membrane, the toughest and
the thickest
2) Arachnoid-middle membrane
below the dura matter
3) Pia matter-the innermost
membrane consisting mainly of
small blood vessels following the
surface of the brain supported by
cerebrospinal fluid
4) Basic nuclei – important centers
for planning, learning movement
sequences
Protection of the brain
5) Cerebral cortex - sensory
information is analyzed, motor
commands are issued & language is generated

30. Surface Anatomy
• Gyri (plural of gyrus)
• Elevated ridges
• Entire surface
• Grooves separate gyri
• A sulcus is a shallow groove (plural, sulci)
• Deeper grooves are fissures

31. The brain has three main parts…
1) Cerebrum
2) Cerebellum
3) Brain Stem
4) Diencephalon
32

32. Parts of Brain
• Cerebrum - also called the
telencephalon, is the largest
portion of the brain in humans
• performs sophisticated
integration; plays major role in
memory, learning, speech,
emotions; formulates complex
behavioral responses
• Divided into four lobes

34. 35

35. Cerebellum
- receives sensory input
from the eyes, ears, joints,
and muscles about the
present position of body
parts, and it also receives
motor output from the
cerebral cortex about
where these parts should
be located.
- After integrating this
information, the cerebellum
sends motor impulses by
way of the brain stem to
the skeletal muscles.

36. • The Brain Stem
connects the brain
to the spinal cord
• The nerves in the
brain stem control
your heartbeat,
breathing, and blood
pressure
37

37. •Hypothalamus – located below the
thalamus. The main visceral control
center of the body and is vitally
important to overall body
homeostasis i.e. autonomic control
center, center for emotional response,
body temperature regulation,
Regulation of food intake, water
balance and thirst, sleep-wake cycles
and control of endocrine system
functioning
Diencephalon
central core of the forebrain and
surrounded by the cerebral
hemispheres
38

38. • Thalamus - specializes in
sense reception
• Epithalamus – the most dorsal
portion of the diencephalon and
forms the roof of the third
ventricle Extending from its
posterior border and visible
externally is the pineal gland.
– The pineal gland secretes the
hormone melatonin (a sleep-
inducing signal and
antioxidant; and, along with
hypothalamic nuclei, helps
regulate the sleep-wake cycle. 39

39. Simplified Function of the Brain…
•Back of brain: perception
•Top of brain: movement
•Front of brain: thinking

40. Spinal cord
http://www.apparelyzed.com/spinalcord.html
• The spinal cord is
the part of the
nervous system
that connects the
brain to the rest of
the nervous
system.
• The spinal cord
sends messages to
the brain.

41. • Responsible for providing sensory
(afferent) information to the central
nervous system
• Carries motor (efferent) commands out to
the body’s tissues
• Includes all neural tissue outside of the
central nervous system
−Somatic nervous system
−Autonomic nervous system
B. Peripheral nervous system
42

42. The peripheral nervous system is
composed of the nerves and the sense
organs.
Ear Eye
Skin
Nerves
Tongue
43

43. Receptors and Sense Organs
• Aristotle classified five
senses, continued to
be regarded as the
classical senses,
although scientists
have determined the
existence of as many
as 15 additional
senses
44

44. Cranial Nerves
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Oh, Oh, Oh, To Touch And Feel Virgin Girl's
Vagina Ahhhh Heaven

45. Spinal Nerves
47

46. Somatic nervous system is
the part of the peripheral
nervous system associated
with the voluntary control of
body movements via skeletal
muscles.
- consists of efferent
nerves responsible for
stimulating muscle contraction,
including all the non-
sensory neurons connected
with skeletal muscles and skin.

47. AutonomicNervousSystem
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48. Parasympathetic Division
- Peaceful, Housekeeping Division
- in control most of the time
- “rest and digest” or “feed and breed” system
- activities that occurs when the body is at rest, especially after eating,
including sexual arousal, salivation, lacrimation, urination, digestion and
defecation
- it functions with actions that do not require immediate reaction
Sympathetic Division
- Stressful, Action Division
- usually speeds up actions like heart rate, blood pressure, breathing
rate
- “fight or flight” system
- the sympathetic division typically functions in actions requiring quick
responses
- preparing the body for intense, energy-consuming activities, such as
fighting, fleeing, or competing in a strenuous game

49. • An automatic reaction without thinking
happens quickly in less than a second.
Reflex arc (Withdrawal)
51

50. The Endocrine System

51. Endocrine System
• “internal” glands of secretion
that release a hormone into the
bloodstream, right within the
gland itself
• influences the metabolic activity
by means of hormones (Gk.
Hormon = to excite), which are
chemical messengers released
into the blood to be transported
throughout the body
• is instrumental in regulating
metabolism, growth and
development, reproduction and
complex behaviors including
parts of our mood, courtship
and migration.
• is the slow message system of
your body

52. Activity of a Hormone-Secreting Cell

53. ENDOCRINOLOGY
ENDOCRINE GLANDS
Functions:
-Regulation of metabolism & nutrient supply
- reproduction and sexual differentiation
- development and growth
- maintenance of the internal environment
HORMONES
-Lacks the ducts
- discrete organs for production and
secretion of chemical substances

54. Chemically, the hormones are of 3 types
57
•Derivatives of the amino acid tyrosine
 e.g. Thyroxine (T4), Triiodothyronine (T3),
Epinephrine and Norepinephrine
•Proteins or peptides
 e.g. Oxytocin, Luteinizing hormone (LH), Prolactin,
Growth hormone (GH), Insulin, Glucagon
•Steroid hormones
 are synthesized from cholesterol e.g. Estrogen
Progesterone, Androgens, Mineralocorticoids,
Glucocorticoids

55. Hypothalamus makes
hormones that control the
pituitary gland. In addition, it
makes hormones that are stored
in the pituitary gland.
Pineal gland releases melatonin, which
is involved in rhythmic activities, such as
daily sleep-wake cycles.
Thyroid produces thyroxine,
which regulates metabolism.
Adrenal glands
release epinephrine and
norepinephrine that
help body deal with
stress.
Pituitary gland
produces hormones that
regulate many of the
other endocrine glands.
Parathyroid glands
These four glands
release parathyroid
hormone, which
regulate the level of
calcium in the blood.
Thymus
releases thymosin
during childhood that
stimulates T cell devt
Testis produce testosterone
responsible for sperm production and
the development of male secondary
sex characteristics
Ovary produces estrogen and
progesterone. Estrogen is necessary
for development of secondary sex
characteristics and eggs.
Progesterone prepares the uterus for
a fertilized egg.
Pancreas
The pancreas produces insulin and
glucagon, which regulate the level of
glucose in the blood.
58

56. Hypothalamus
• The main control
center of the
endocrine system
• makes hormones that
control the pituitary
gland.
• In addition, it makes
hormones that are
stored in the pituitary
gland

57. Pituitary Gland
• pea-sized gland
consisting of two
distinct parts: a
posterior lobe and an
anterior lobe, both
situated in a pocket of
skull bone just under
the hypothalamus
• produces hormones
that regulate many of
the other endocrine
glands

58. Pineal Gland
• a pea-sized mass of
tissue near the center
of the brain
• releases melatonin,
which is involved in
rhythmic activities,
such as daily sleep-
wake cycles

59. Thyroid Gland
• located in the neck
just under your
larynx (voice box)
• produces thyroxine,
which regulates
metabolism.

60. Thymus
• lies under the
breastbone in
humans
• releases
thymosin during
childhood that
stimulates T cell
devt

61. Parathyroid Gland
• These four glands
release parathyroid
hormone, which
regulate the level of
calcium in the
blood

62. Adrenal Gland
• one sitting on top of
each kidney
• release epinephrine
and norepinephrine
that help body deal
with stress.

63. Pancreas
• The pancreas
produces insulin
and glucagon,
which regulate the
level of glucose in
the blood

64. Testes
• produce testosterone
responsible for sperm
production and the
development of male
secondary sex
characteristics

65. Ovaries
• produces estrogen
and progesterone.
• Estrogen is necessary
for development of
secondary sex
characteristics and
eggs.
• Progesterone
prepares the uterus
for a fertilized egg.

66. Concept Map
69

67. Hypothalamus and Pituitary gland
• Hypothalamus – in vertebrates,
this is part of the brain and helps
regulate the internal environment of
the body; for example in the control
of heart rate, body temperature and
water balance. This also controls the
glandular secretions of the pituitary
gland
• Pituitary gland- this is a small
gland that lies just inferior to the
hypothalamus; this consist of the
anterior and posterior pituitary both
produce hormones. It is also called
the “master gland” because many
of its hormones regulate the other
endocrine function

68. Actions of Insulin and Glucagon
71
Liver converts
glucose to
glycogen

69. The Menstrual Cycle
72

70. Principal Endocrine Glands & Hormones in the body
Endocrine
gland
Hormones released Target
Tissues/Organs
Function(s) of Hormone
Hypotha-
lamus
Hypothalamic-
realeasing and
releasing inhibiting
Anterior pituitary Regulate anterior
pituitary hormones
Posterior
pituitary
Antidiuretic (ADH)
Oxytoxin
Kidney
Uterus,
mammary gland
Stimulates water
reabsoprtion by kidneys
Stimulates uterine muscle
contraction, release of
milk by mammary glands
Anterior
pituitary
Thyroid-stimulating
(TSH)
Adrenocortico-trophic
(ACTH)
Gonadotrophic
(follicle
stimulating,FSH)
Thyroid
Adrenal Cortex
Gonads
Stimulates thyroid
hormone
Synthesis adrenal cortex
Egg and sperm
production and sex
hormones

71. Anterior
pituitary
Luteinizing
hormone (LH)
Gonads Egg and sperm
production and sex
hormones
Prolactin (PRL) Mammary
glands
Milk production
Growth (GH) Soft tissues,
bones
Cell division, protein
synthesis and bone
growth
Melanocyte
stimulating (MSH)
Melanocytes in
skin
Unknown function in
humans
Regulates skin color
in lower vertebrate
Thyroid Thyroxine (T4)
and
triiodothyronine
(T3), Calcitonin
All tissues
Bones,kidneys,
intestine
Increase
Lowers blood calcium
level
Thymus Thymosin Stimulates T cell
development
Endocrine
gland
Hormones released Target
Tissues/Organs
Function(s) of
Hormone

72. Para-
thyroid
Parathyroid
(PTH)
Bones, kidneys,
intestine
Raises calcium in
blood
Adrenal
cortex
Glucocorticoids
(cortisol)
All tissues Raise blood glucose
level; stimulate
breakdown of protein
Mineralcorticoids
(cortisol)
All tissues Reabsorb sodium and
excrete potassium
Sex hormones Gonads, skins,
muscles, bones
Stimulate
reproductive organs
Adrenal
medulla
Epinephrine
and
nonepinephrine
Cardiac and
other muscles
Emergency
situations; raise
blood glucose level
Endocrine
gland
Hormones
released
Target
Tissues/Organs
Function(s) of
Hormone

73. Pancreas Insulin Liver, muscles,
adipose tissues
Lowers blood glucose
level; promotes
formation of glycogen
Glucagon Liver, muscles,
adipose tissues
Raises blood glucose
level
Testes Androgens
(testosterone)
Gonads, skins,
muscles, bones
Stimulates secondary
male sex characteristics
Ovaries Estrogens
and
progesterone
Gonads, skins,
muscles, bones
Stimulates female sex
characteristics
Pineal
gland
Melatonin Brain Circadian and circannal
rhythms; possibly
involved in maturation
of sex organs
Endocrine
gland
Hormones
released
Target Tissues/
Organs
Function(s) of
Hormone

74. Endocrine Diseases and Disorders
Disease Effects of deficiency/excess
Diabetes mellitus
(Type I)
is characterized by destruction of the beta cells of the
islets of Langerhans and a complete lack of insulin.
Diabetes mellitus
(Type II)
insulin is produced but cannot exert its effects
because of a deficiency of insulin receptors on cell
membranes
Diabetes insipidus
Deficiency of vasopressin, one of the antidiuretic
hormones (ADH) thus, abnormal increase in urine
output
Hyperthyroidism
Underactive thyroid gland, cause myxedema and
cretinism, known as congenital hypothyrodism.
Characterized by enlargement of the thyroid gland,
most often called thyroid goiter
Grave’s disease
an autoimmune disease in which specific antibodies
are produced , producing an excessive amount of
thyroid hormones

75. Endocrine Diseases and Disorders
Hypocalcaemia when the blood levels of calcium are low
Hypoparathyroidism
insufficient secretion of parathyroid hormones
which leads to increased nerve excitability
Addison’s disease
Decreased function of the adrenal cortex result to
weakness, fatigue, abdominal pains, nausea,
dehydration, fever and hyperpigmentation (tanning
withought sun exposure) are among the symptoms
Cushing’s
Syndrome
Excessive secretion of glucocorticoids;
corticosteroid produced by the adrenal glands
Hypoglycemia
the clinical syndrome that results from low blood
sugar
Acromegaly and
gigantism
Both are caused by a pituitary tumor that
stimulates production of excessive growth
hormone, causing abnormal growth in particular
parts of the body
Pituitary dwarfism
Growth hormone deficiency in children results in
slowed long bone growth

76. Hyperthyroidism
Grave’s disease
Gigantism
Pituitary dwarfism