Anatomy and Physiology 2

Transcription

1 Anatomy and Physiology 2

2 The Nervous System Nerves allows organisms to detect and respond to stimuli by transmitting electrical impulses cell to cell. Can send info at high speeds! Neurons are the smallest units of the nervous system. Video: PNwqm0mM

3 Structure and Function of a Neuron Dendrite -- neuron branch (like a tree) to detect stimuli from other neurons Cell body -- body (soma) of the neuron where metabolic activities occur

4 Structure and Function of a Neuron Axon -- the long trunk of the nerve covered by a myelin sheath (which provides electrical insulation) carries the nerve impulse from one end to the other

5 Structure and Function of a Neuron Axon terminals -- the end of the nerve releases nerve chemicals called neurotransmitters which jump across empty space to stimulate the dendrites on the next nerve cell

6 Neurotransmitters

7 Central Nervous System- Brain and Spinal Cord Spinal Cord A thick bundle of nerves enclosed in the vertebrae for protection Connects the base of brain to the rest of body Includes automatic responses too

8 Central Nervous System- Brain and Spinal Cord Brain A huge mass of neurons inside the cranium Three divisions:

9 Central Nervous System- Brain and Spinal Cord Cerebrum Interprets sensory impulses origin of conscience activities memory, thinking and reasoning

10 Central Nervous System- Brain and Spinal Cord Cerebellum coordinates motor activities helps maintain balance

11 Central Nervous System- Brain and Spinal Cord Medulla oblongata controls involuntary activities breathing heart beat blood pressure coughing digestive organs

12 Peripheral Nervous System- All the other nerves! Two types: Somatic nerves- controls voluntary muscles Autonomic nerves- controls areas NOT under conscious control ex.

13 Blood vessels in head

14 Human Head Transplant html

15 Human Behavior Involuntary behavior- no conscious control Simple reflexes- automatic, inborn behavior Conditioned behavior- learned behavior Habits- repetition of an action that establishes pathways for nervous impulses

16 Human Behavior Voluntary behavior- conscious control Uses memories association of ideas, imagination of possible results of actions and judges which particular response to take

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19 Malfunctions of the Nervous System Meningitis- inflammation of membranes that surround the brain and spinal cord (caused by bacteria or virus) Cerebral palsy- damage to motor centers of the brain Polio- disease of the spinal cord caused by a virus Destroys motor neurons in spinal cord and causes paralysis of the muscles controlled by those neurons

20 Endocrine System Cell Membrane Receptors Many cell membranes have receptor molecules on their surface. These receptor sites play an important role in allowing cells and organs to communicate with one another.

21 Hormonal Regulation A hormone is a chemical messenger with a specific shape that travels through the bloodstream influencing another target cell or target organ. Upon reaching the cell the hormone is targeted for, the hormone activates a gene within a cell to make a necessary compound.

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23 Hormonal Regulation Important glands include: The pituitary gland at the base of the brain makes growth hormone, thyroid and follicle stimulating hormones. The thyroid gland regulates the rate of metabolism, physical and mental development. (Iodine needed) Adrenal glands above the kidneys secrete adrenaline to increase heartbeat and blood clotting rates. The Islets of Langerhans in the pancreas secretes insulin to absorb sugar from the blood vessels by storing it as glycogen in the liver Gonads for creating sex cells is stimulated by estrogen and testosterone.

24 Hormonal Feedback Mechanism Any change in nerve or hormone signals will change the communication between cells and organs in an organism and thus may cause problems for organism s stability and ability to maintain homeostasis.

25 Hormonal Feedback Mechanism Feedback is when a change in one quantity causes a change in a second quantity which then causes a change in the first quantity. Negative feedback is when the change caused by the feedback is opposite to the initial change.

26 Negative Feedback

27 Malfunctions of the Endocrine Glands Goiter Enlargement of the thyroid (in the throat) caused by not enough iodine in the diet.

28 Malfunctions of the Endocrine Glands Diabetes Excessive sugar in the blood is caused by a deficiency of insulin produced by the islets of Langerhans in the pancreas. Regular injections of insulin is needed to control the disease.

29 Crash Course: Endocrine

30 Immune System and Disease Disease Homeostasis in an organism is constantly threatened. Failure to respond effectively can result in disease or death Disease is a disturbance of homeostasis or steady state within an organism. Many organisms, such as viruses, bacteria, fungi, and parasites may cause disease.

31 Immune System and Disease Disease also results from factors which are not living organisms. The immune response is the defensive reaction of the body to foreign substances or organisms. The immune system also protects against some cancer cells which may arise in the body.

32 Some Causes of Disease Living organisms which cause disease are known as pathogens Examples viruses bacteria fungi parasites like worms

33 Some Causes of Disease Other factors may be involved which contribute to or cause the body to develop disease. Includes: Heredity exposure to poisonous (toxic) substances poor nutrition, organ failure or malfunction poor personal behavior and choices

34 Some Causes of Disease Smoking, obesity, and over consumption of alcoholic beverages would be a few examples of poor personal choices which may have immediate or long term consequences for our health.

35 Immunity and Disease Immunity describes the ability of an organism to resist foreign organisms or invaders which enter its body. The immune system is designed to protect against microscopic organisms (bacteria, viruses) and foreign substances which enter an organism from outside its body. The immune system also protects from many cancer cells which arise within our bodies.

36 Immunity and Disease An antigen is any foreign substance which invades the body of an organism, while a pathogen is a living antigen (such as viruses or bacteria) which invade an organism.

37 White Blood Cells Many different kinds of white blood cells exist which are able to help the body fight foreign invaders in various ways. These various ways include: engulfing (eating) invaders (phagocytes are white blood cells doing this) producing antibodies (chemicals which destroy or neutralize antigens) (lymphocytes are the kind of white blood cells which produce antibodies) marking antigens for attack and killing by other white blood cells

38 THE IMMUNE SYSTEM'S LINES OF DEFENSE First line: Keep the pathogens out Skin Mucus Nose Hairs Sweat Stomach Acids Tears

39 THE IMMUNE SYSTEM'S LINES OF DEFENSE Second Line: The inflammatory response a generalized reaction to infection Swelling from increased blood flow Increase in temperature at infection and/or as a fever Destruction of infected cells (and some healthy surrounding cells too)

40 THE IMMUNE SYSTEM'S LINES OF DEFENSE Third Line: A specific attack on pathogens and infected cells Release of antibodies - proteins that attach to the surface proteins of pathogens, deactivating them.

41 Immune System Memory When organisms are exposed to disease, they make specific antibodies which destroy that antigen during their first exposure to it. This first exposure to a disease and our making of antibodies in reaction to this to defend ourselves is sometimes called the primary immune response.

42 Immune System Memory Our immune system has a memory. This means that if we ever are exposed to that same particular disease antigen again, our immune system has a memory and will make antibodies so rapidly in response to another exposure that we will not get the disease. Our immune memory is sometimes called the secondary immune response.

43 Vaccinations Vaccinations use dead or weakened microbes or parts of them to stimulate the primary immune response or first production of antibodies. Using dead or weakened microbes has the advantage of not making the organism sick as they would become if they caught and recovered from a disease.

44 Vaccinations Because the vaccine has stimulated the immune system, the organism will now have a memory for subsequent exposures to that disease causing antigen. Vaccines prevent diseases, they don't cure you!

45 Allergies and Auto-immune Diseases In allergies, the body's immune system produces chemicals in response to normally harmless substances which do not trouble other individuals. ex. Peanuts These chemicals make people with allergies feel sick.

46 Allergies and Auto-immune Diseases In auto-immune diseases, the body's immune system for usually unknown reasons may attack and destroy some its own cells. Some kinds of arthritis and degenerative diseases result from auto-immune diseases.

47 AIDS, Cancer, and Disease Research Some viral diseases damage the immune system which leaves it unable to cope with many antigens and other infectious agents. AIDS is a viral disease which destroys the ability of the immune system to produce antibodies, so the afflicted individual is unable to cope with infections and cancer cells which arise within the body.

48 AIDS, Cancer, and Disease Research Cancer is a group of diseases resulting from gene mutations which cause cells to divide uncontrollably. Exposure of cells to certain chemicals and radiation appears to increase the chance of mutations and thus cancer.

49 AIDS, Cancer, and Disease Research Biological research is constantly ongoing to find knowledge about diagnosing, preventing, treating, controlling and curing diseases in plants and animals. The human genome project has provided a great deal of information of the genetic basis of many diseases.

50 Blood Types Blood is classified as A, B, or O depending on the presence or absence of antigens. When giving blood transfusions, it is important to consider the importance of the blood type of the recipient and donor. Blood type O is a universal donor Type AB is the universal acceptor