1. REGULATION
Biology-Unit 9

2. Definition
The life function by which an organism Controls and Coordinates its other life functions to maintain existence.
Includes both Nervous Control (some organisms) and Chemical Control (all organisms).
-Responses are very rapid short in length in the nervous system, slower and longer lasting in the endocrine (hormone) system.

3. Parts of the nervous system
1. Neurons – basic functional units of the human nervous system.
-Neurons are cells specialized for the transmission of nerve impulses from place to place in the body.

4. Typical Neuron Nucleus Axon terminals Cell body Myelin sheath Nodes
Dendrites

5. Neurons are made of the following:
Dendrites – fibers that serve to detect a stimulus and direct an impulse toward the cell body.
Cell body – the main cell body, containing most of the cytoplasm, nucleus, and other organelles.
-It is here that the nerve impulse is generated.

6. Neurons are made of the following:
Axon – an elongated portion of the neuron that carries the nerve impulses from the cyton toward the terminal branches.
Terminal Branches – fibers leading from the axon of the nerve cell that reach toward the dendrites of adjacent neurons and secrete chemical neurotransmitters. TERMINAL means ENDING, so this is the last place that a signal goes in the neuron.

7. Neurons are made of the following:
Synapse- the gap that occurs between adjacent neurons.
-A special chemical, called a neurotransmitter, is necessary in order to transmit this signal across the synapse.
Neurotransmitter – special chemicals (acetylcholine) produced and secreted by the neuron’s terminal branches.
-Carries the nerve impulse across the synapse.

8. Neurons are made of the following:

9. Three types of Neurons:
a. Sensory neurons– receives stimuli from environment and transmits to central nervous system (CNS) for interpretation.

10. Three types of Neurons:
b. Interneurons – located in central nervous system. Interprets sensory impulses and transmits “commands” to motor neurons.

11. Three types of Neurons:
c. Motor Neurons– carries impulse from “command centers” in central nervous system (CNS) to effector organs (muscles or glands) where a response is initiated.

12. Organization of Neurons
Nerves – bundles of neurons
-May contain single type of neuron (sensory or motor nerves) or two separate types (mixed nerves).
Central Nervous System (CNS) – consists of the brain and spinal cord.
Peripheral Nervous System: all the other nerves in your body

13. The Central Nervous System
The Brain – large organ composed of a mass of interneurons located in cranial cavity.
-The Brain is highly specialized and subdivided into three major regions: The Cerebrum, Cerebellum, and Medulla

14. Parts of the Brain Cerebrum Thalamus Pineal gland Hypothalamus
Cerebellum
Pituitary gland
Pons
Medulla
Spinal cord

15. Parts of the Brain 1. Cerebrum – largest portion of the brain
-Regulates: conscious thought, memory,
sense interpretation, reasoning, and other voluntary activities.

16. Parts of the Brain 2. Cerebellum – located at the rear of cranium.
-Responsible for coordinating muscular activities and balance (cerebalance).

17. Parts of the Brain Medulla – Located at the base of brain.
-Regulates the automatic, rhythmic processes of the body
Ex. Heart beat, Peristalsis, rate of breathing, etc.

18. The Spinal Cord
Continuous with the brain, starts in the area of the medulla, then extends downward from the base of the brain along the dorsal surface of the body.
-Encased within the bony vertebral column (for protection).
-Connects brain to peripheral nerves

19. Reflex Arc-Definition
A rapid response made possible by a series of three neurons working together.

20. Reflex Arc-Components
Receptor – A specialized structure sensitive to specific stimuli, they are found in sensory organs.
-A Stimulus is anything that can cause a change in activity by triggering a nervous impulse.

21. Reflex Arc-Components
Sensory Neuron – receives a stimulus in a receptor.
Interneuron (in the Spinal Cord) – interprets the sensory neurons impulse.

22. Reflex Arc-Components
Motor Neuron – Carries impulses from the spinal cord to an effector.
Effector – A muscle or a gland that works in response to a stimulus.
Reflexes are so rapid and automatic that many are complete before our cerebrum makes us aware of the stimuli initiating them.

23. Peripheral Nervous System (PNS)
-All the types of nerves that branch from the Central Nervous System.
Somatic Nervous System – the nerves that control the actions of the voluntary skeletal muscles.
Autonomic Nervous System – nerves regulating automatic functions (glands/involuntary muscles).

24. Peripheral Nervous System (PNS)

25. Malfunctions of the Nervous System
Cerebral Palsy – group of congenital (birth) defects of the muscle and speech centers of the brain.
Meningitis – inflammation of the meninges (membranes covering brain and spinal cord).
Alzheimer’s disease- a chronic condition involving breakdown of the neurons in the brain (currently there is no cure)
Multiple Sclerosis—the wearing away of the myelin sheath that protects the axon.

26. Malfunctions of the Nervous System
Stroke – brain function is impaired or destroyed by lack of oxygen.
A blood clot restricts blood flow to the brain or blood vessels burst in brain (cerebral hemorrhage).

27. The Endocrine System (Chemical Control of Organisms)
In animals, hormones are produced and secreted by specialized Endocrine Glands.
These glands are ductless (no tubes) and secrete hormones directly into the circulatory system.
These hormones travel throughout the body but affect only specific target cells and organs
Nervous system responses are fast and short lived, endocrine responses are slow and long lasting

28. The thyroid produces thyroxine, which regulates metabolism.
Hypothalamus
The hypothalamus makes hormones that control the pituitary gland. In addition, it makes hormones that are stored in the pituitary gland.
Pineal gland
The pineal gland releases melatonin, which is involved in rhythmic activities, such as daily sleep-wake cycles.
Thyroid
The thyroid produces thyroxine, which regulates metabolism.
Pancreas
The pancreas produces insulin and glucagon, which regulate the level of glucose in the blood.
Ovary
The ovaries produce estrogen and progesterone. Estrogen is required for the development of secondary sex characteristics and for the development of eggs. Progesterone prepares the uterus for a fertilized egg.
Testis
The testes produce testosterone, which is responsible for sperm production and the development of male secondary sex characteristics
Pituitary gland
The 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
During childhood, the thymus releases thymosin, which stimulates Tcell development.
Adrenal glands
The adrenal glands release epinephrine and nonepinephrine, which help the body deal with stress.

29. The Human Endocrine System
Glands
Hypothalamus – Small gland located within the brain. The hormonal secretions of the hypothalamus control the pituitary gland.

30. Glands Pituitary Gland – Located under the brain.
Known as the master gland since such a large number of hormones are produced there.

31. Glands
Ex.
-Growth Hormone – targets all cells and affects growth of long bones.
-Follicle Stimulating Hormone – targets gonads and affects females monthly cycle, production of female sex hormones and male gametes.
-Thyroid Stimulating Hormone – Targets thyroid gland and affects production and release of thyroxin.

32. Glands Thyroid Gland – Located in the neck, surrounding the trachea.
-Produces and releases thyroxin, a hormone which regulates the metabolic rate.
-Depends on a dietary supply of Iodine.

33. Glands
Parathyroid Gland – located inside the thyroid gland. The parathyroid produces and secretes parathormone.
-Parathormone targets bone and controls the metabolism of calcium in the body.

34. Glands
Adrenal Glands – Located in the kidneys and consist of two separate regions:
1)Adrenal Cortex (outer region)
a) Secretes aldosterone which targets the kidneys and controls water balance and blood pressure in the body.
b) Cortisol, which targets the liver and controls the conversion of stored starches (glycogen) into simple sugars (glucose)

35. Glands 2)Adrenal Medulla (inner region)
-Secretes adrenalin which affects the body’s response to danger.
-Adrenalin increases the breathing rate, heart rate, and metabolism.
-It also stimulates the conversion of glycogen into simple sugars used for a quick source of fuel.

36. Glands
Pancreas (Inlets of Langerhans) – gland tissue scattered throughout the pancreas.
Produces both insulin and glucagon

37. Glands
Insulin and glucagon have opposite effects on the body’s storage of sugar. Both hormones target cells of the liver.
Insulin promotes sugar storage in the liver
Sugar travels from Blood  Liver (Lowers blood sugar)
Glucagon promotes the release of stored sugar from the liver.
Sugars travel from Liver  Blood (Increases blood sugar)

38. Glands Gonads (Sex Glands)
Male gonads are the testes which produce Testosterone.
-Testosterone targets male sex organs and affects gamete (sperm) production, and male secondary sex characteristics.
Female gonads are the ovaries which produce estrogen and progesterone.
-These hormones control female secondary sexual characteristics and female sexual functions (menstrual cycle and pregnancy).

39. Negative Feedback Control
The body’s mechanism that controls the endocrine system.
This control returns hormone levels to normal levels and prevents the secretion of hormones that are not needed.

40. Negative Feedback Control
Beta cells release insulin into the blood
Body cells absorb glucose
Blood glucose level increases
Blood glucose level decreases
Liver converts glycogen to glucose
Homeostasis: Normal blood glucose level
Blood glucose level decreases
Blood glucose level increases
Liver converts glycogen to glucose
Alpha cells release glucagon into blood

41. Malfunctions of the Endocrine System
Goiter – An enlargement of the thyroid gland. A goiter is caused when the thyroid is unable to produce thyroxin due to the body’s lack of Iodine.

42. Malfunctions of the Endocrine System
Diabetes – The body’s inability to remove sugar from the blood and store it as glycogen in the liver. There are two causes.

43. Malfunctions of the Endocrine System
The first cause is the body does not produce enough insulin.
The cells do not receive the message to take glucose out of the blood.
This is called Type I or Juvenile Onset Diabetes.

44. Malfunctions of the Endocrine System
The second cause is when receptors on the surface of the cells no longer recognize insulin as a hormone messenger.
They ignore the signal to remove glucose from the blood.
This is called Type II or Adult Onset Diabetes.