1. The Nervous System

2. Neuron – working unit of the nervous
system

3. Axon – carries messages away from the cell body

4. dendrites – receive the messages and send
them to the cell body

5. Terminal Bud – send messages to other neurons

6. 3 types of neurons
• Sensory neurons – send info to the spinal
cord or brain
• Interneurons – send info out of brain and
spinal cords to the motor neurons
• Motor neurons – send info from brain and
spinal cord to muscles or glands

7. Sensory neuron Motor neuron
(hand) (arm)
Interneuron

8. Synapse
• Small space in between neurons
• Neurotransmitters are released in the
synapse and starts an impulse in the next
neuron

9. Synapse

10. Divisions of the Nervous System
CNS – central nervous system – brain and
spinal cord
PNS – peripheral nervous system – all the
nerves outside the CNS

11. Central Nervous System
• Brain 100 billion neurons
• 3 major parts

12. 1. Cerebrum
• Divided into
hemispheres
• Memory is stored

14. Cerebrum

17. 2. Cerebellum
• Under the cerebrum
• Coordinated
voluntary muscle
movements

18. 3. Brainstem
• Connects the brain to
the spinal cord
• Made up of the
– Mid brain
– Pons
– Medulla
• Controls homeostasis
of heart, breathing,
blood pressure,
involuntary muscle
movements

19. Peripheral Nervous System
• 2 divisions of the peripheral nervous
system

20. Peripheral
Nervous System
Somatic Autonomic
Nervous System Nervous
System
Skeletal Heartrate,
Muscle breathing,
digestion, salivary
glands

21. Reflex
• Involuntary response to a stimulus
• Involves a pathway called a
(reflex arc) over which impulses
travel

22. Reflex arc
1. Impulse is sent to the spinal cord
2. Impulse passes to an interneuron in the
spinal cord which immediately relays the
impulse to motor neurons
3. Motor neurons transmit the impulse to
muscles in your arm
4. Your arm pulls back (Without thinking!)

23. Steps of a reflex arc
1. Receptor
2. Sensory neuron
3. Interneuron (spinal cord)
4. Motor neuron
5. Effector – “response”

26. Your Endocrine System

27. Endocrine system
• System of glands that release their
products into the blood stream and
broadcast messages throughout the body

28. Hormones
• Affect specific tissues called target cells
Target cells – control activities in parts of the
body other than right around the gland

29. Glands of the Endocrine
System

30. Hypothalamus
• Part of the brain
• Produces hormones that
influence the pituitary gland

32. Pituitary Gland
• “Master Gland”
• Secretes numerous hormones
• Growth-stimulating Hormone
• Hormones to control specific glands
• Thyroid Stimulating Hormone (TSH)
– Tells thyroid to produce thyroxine
• The Follicle Stimulating Hormone
– Stimulates activity in the ovary and
testes

34. Thyroid Gland
• Located in the neck
• Makes thyroxine
• Regulates metabolism

36. Parathyroid Glands
• Embedded in the thyroid gland
• Secrete parathormone
• Controls the metabolism of
calcium
• Necessary for nerve function,
blood clotting, and proper growth
of teeth and bones

38. Adrenal Glands
• Two glands located on top of the
kidneys
• Each gland has 2 distinct regions

41. Adrenal Cortex
• Secretes two types of steroid
hormones
1. promotes the conversion of body fat
and protein into glucose
2. promotes the reabsorbtion into the
blood stream of sodium and chloride
ions by the kidney tubules
– This affects the water balance and
maintains BP

42. Adrenal Medulla
• Secretes adrenalin in times of
emergency
• Increases the blood sugar level
• Speeds heart and breathing rates

44. Islets of Langerhans
• Located in the pancreas
• Secrete insulin and glucagon

46. Insulin
• Helps take glucose into cells
• Lowers blood sugar levels by
taking it out of the blood and
storing it in the liver and muscle
cells

47. Glucagon
• Stimulates the release of sugar
from the liver
• Raises blood sugar level

48. Gonads
• Sex glands
• Testes
• Secrete testosterone – develop
male secondary sex characteristics
• Ovaries
• Secrete estrogen - develop female
secondary sex characteristics

51. Endocrine Control
• Negative feedback system
• Controls the amount of hormone
an endocrine gland produces
• Works like a thermostat in your
house

52. Negative feedback system
Start: 1. Hormone level low
2. Hormone production increases
3. Hormone level high
4. Hormone production slowed
down
End: 5. Hormone level low

53. Endocrine Feedback System of
TSH
Hypothalamus
In hibits
Thyroxin
Pituitary Gland
Thyroid Gland
Thyroid
stimulates
Stimulating
Hormone

54. Endocrine System Disorders

55. Goiter
• Enlargement of the thyroid gland
• Results in not being able to make
thyroxine
• Often associated with iodine
deficiency in the diet

58. Diabetes
• Insulin deficiency
• Results in an elevated blood
sugar level
• Also an inability of the body to
store the sugar glycogen in the
liver