Notes for Module 7 DBA

Lesson 7.01 Nervous and Endocrine Systems
Neurons: A nerve cell, the fundamental unit of the nervous system that conducts electrical signals through the body.
Impulses: Electrical signals conducted through the body's nervous system by neuron cells.
Electrical signals called impulses are carried throughout the nervous system by specialized cells called neurons.
Neurons cells can vary in shape, size, and specialized function, but they all share some common features.
The cell body is the largest part of the neuron. It contains the nucleus, other organelles, and most of the cytoplasm.
Dendrites are short, branched extensions that spread out from the cell body.
The axon is a long, branching extension that carries impulses away from the neuron's cell body to other neurons.
The end, or terminal, of the axon contains tiny vesicles filled with neurotransmitters, chemicals that transmit an impulse from the axon of one neuron to the dendrites of a neighboring neuron.
Sensory and motor neurons carry signals to and from the spinal cord and brain, while the interneurons in the spinal cord and brain process received signals and send out new signals for the appropriate bodily response.
Central nervous system: Includes the brain and spinal cord, processes information and creates a response that is delivered to the appropriate parts of the body.
Peripheral nervous system: Network of neurons and supporting cells that carries impulses into and out from the central nervous system.
The two halves of the nervous system work together in order for your body to properly communicate its sensations and needs.
The brain sends messages via the spinal cord to the body's peripheral nerves, which control the muscles and internal organs.
Lesson 7.02 Respiratory and Circulatory
The respiratory and circulatory systems work together to carry oxygen to the body's cells and to remove carbon dioxide from those cells.
The main function of the respiratory system is to exchange these gases with the environment.
A major function of the circulatory system is to transport the gases between the respiratory system and other parts of the body.
The human respiratory system is made up of the nose, pharynx, larynx, trachea, bronchi, and lungs.
The rib cage and rib muscles are not part of the respiratory system, but they are important to its function.
They work with the diaphragm to cause inhalation and exhalation. You can often observe your rib cage expanding and contracting as you breathe.
The Circulatory System has three very important functions:
Delivers materials throughout the body, such as oxygen and various important nutrients.
Removes waste from the body, such as carbon dioxide.
Fights disease and seals cuts to prevent blood loss.
The heart is divided into four chambers, with a wall called a septum separating the right side of the heart from the left.
The septum is important because it separates oxygenated and deoxygenated blood and prevents it from mixing.
Red blood cell: Blood cell that contains hemoglobin and carries oxygen.
White blood cell: Blood cell that protects against infection and attacks parasites and bacteria.
Platelet: Cell fragment released by bone marrow that helps in blood clotting.
Blood pressure: The force that blood circulation exerts against the wall of a blood vessel.
Systolic pressure: The maximum pressure exerted when the heart contracts and pumps blood out into the body.
Diastolic pressure: The minimum pressure exerted when the heart relaxes and dilates between pumps.
Cardiovascular disease: Diseases of the heart and blood vessels.
Lesson 7.03 Digestive and Excretory
ATP: Adenosine triphosphate, the compound used by cells to store and release energy.
Molecules in food contain chemical energy that is used to produce ATP, the molecule that powers most operations within a cell.
In addition, food and water supply our cells with the raw materials needed to grow, divide, and repair.
Lesson 7.04 Muscular, Skeletal, and Integumentary
Skeletal system: The hard structure (bones and cartilages) that provides an internal support system for the body.
The human skeleton can be divided into two regions: the axial skeleton and the appendicular skeleton.
Axial skeleton: The bones that support the central axis of the body, including the skull, vertebral column, and rib cage.The axial skeleton is made up of the skull, mandible, and the vertebrae in the spinal column.
Appendicular skeleton: The bones of the arms, legs, pelvis, and shoulder areas.
The appendicular skeleton is made up of the rest of the bones, such as those in the arms and legs.
A place where two bones meet is called a joint. All joints contain connective tissue that holds the bones together.
Some joints, like those in the shoulder or hip, allow a range of movements while others, such as the joints in the adult skull, do not allow any movement at all.
Fixed or immovable joints; These joints are places where two or more bones are interlocked and do not move.
Slightly movable joints; These joints allow small amounts of movement.
Freely movable joints; These joints allow movement in two or more directions and include the joints in the shoulders, knees, and elbows.
Synovial fluid acts as a lubricant to reduce friction between the bones.
Muscular system: The bodily system composed of skeletal, smooth, and cardiac muscle tissue, that functions in the movement of the body or the movement of materials through the body.
The muscular system includes the muscles you use and build when lifting weights at the gym, and also thousands of tiny muscles throughout your body that move the organs and vessels in the circulatory and other systems.
Skeletal muscles are usually attached to bones by tendons.
Smooth muscles are found throughout the body in the walls of organs and structures such as the stomach, blood vessels, and intestines.
Cardiac muscle forms the contractile wall of the heart. It shares similarities with both skeletal and smooth muscles.
Skeletal muscles are connected to bones by tough connective tissues called tendons.
If a bone is the lever, then the joint acts as a fulcrum.
Lever: A simple machine made up of a rigid bar pivoted on a fixed point, or fulcrum; used to transmit force, such as raising or moving an object at one end by pushing down on the other.
Fulcrum: A fixed point around which a lever moves.
Integumentary system, The skin and related structures that cover and protect the body.
Skin is part of the integumentary system, which also includes hair, nails and related glands.
The largest organ in your body is skin.
Skin is made up of three main layers:
The epidermis is the skin’s outermost layer.
The exposed top layer of the epidermis is made up of dead cells.
Underneath that is a layer of living cells that are dividing rapidly in order to produce new skin cells.
The layer under the epidermis is called the dermis.
This layer of skin contains blood vessels, smooth muscles, nerve endings, hair follicles, and sweat glands.
These structures contained within the dermis help the body to receive information and to maintain body temperature.
The hypodermis is the innermost layer of the skin, which is made up of loose connective tissue and fatty tissue.
It serves as an insulator and shock absorber, while also anchoring the skin to the organs below.
Lesson 7.05 Reproductive System
Estrogen: A group of hormones that stimulate development of female secondary sexual characteristics, produced in the female ovaries but in lesser amounts in other organs.
Testosterone: A hormone that stimulates development of male secondary sexual characteristics, produced in the male testes and also in lesser amounts in the female ovaries.
Gonads: The male and female sex organs that produce gamete cells, testes in males and ovaries in females.
These hormones are produced in the gonads, and they act on cells and tissues to produce many of the physical characteristics associated with males and females.
Sperm: A male gamete, or haploid reproductive cell, produced in the testes and involved in the fertilization of a female egg.
By the time puberty is complete, the male reproductive system is fully functional and the male can produce and release active sperm.
During the reproductive years that follow puberty, the woman’s reproductive system undergoes a regular menstrual cycle that lasts an average of 28 days.
The sperm’s haploid nucleus then fuses with the egg’s haploid nucleus to form one diploid nucleus with a full set of 46 chromosomes.
This fertilized cell is called a zygote, but is can also be referred to as an embryo.
When sperm cells are released in the vagina, they swim through the narrow cervix, into the uterus, and up into the fallopian tubes.
If an egg is present in one of the tubes, it can be fertilized.
Lesson 7.06 Immune System
Pathogens: A virus or microorganism (bacteria, fungi, and protists) that causes disease in its plant or animal host. (Greek pathos: “suffering,” gen-: “give birth to”)
Our bodies have a series of defenses that help protect against disease-causing pathogens and other foreign substances.
Have you ever had an infected splinter that becomes red and swollen? This is an example of the body’s inflammatory response, which occurs when invading pathogens trigger the body to release chemicals called histamines.
These histamines increase the blood flow to the infected area, causing the area to swell.
Many of these white blood cells are phagocytes, cells that engulf and destroy invading bacteria cells.
Another nonspecific response to an infection is an increase in body temperature called a fever.
Antibody: A protein that either attacks antigens directly or produces antigen-binding proteins.
Lymphocytes: A type of small white blood cell produced in the lymphoid tissue, including T cells and B cells.
The functions of the immune system include production of specific defense proteins called antibodies as well as the participation of white blood cells called lymphocytes.
Molecules called antigens can be found on the outer surface of bacteria, viruses, parasites, pollen, insect venom, and transplanted tissues.
Each antigen has a unique molecular shape that stimulates production of a corresponding antibody.
The white blood cells involved in the specific defenses of the immune system are primarily B lymphocytes (B cells) and T lymphocytes (T cells).
The immune system uses memory cells to remember antigens it has encountered in the past in order to react against them more rapidly and effectively on future exposures.
This is called an active immunity, because it involves a response by a person’s own immune system.
An active immunity that results from a person acquiring memory cells after recovering from an infectious disease is a naturally acquired active immunity.
Deliberate exposure to an antigen through a vaccine results in an artificially acquired active immunity. Vaccines may be living but weakened microorganisms, inactivated bacterial toxins, or killed microorganisms
Antibodies produced by animals or other individuals can sometimes be introduced into a person’s blood, resulting in a passive immunity.
Antibiotics are medications that can be used to kill bacteria, but they are not effective against viruses like a cold or flu.
Antimicrobial: Capable of destroying or inhibiting the growth of disease-causing pathogens.
Antiseptics are antimicrobial substances applied to skin or living tissue to reduce the possibility of infection.
Disinfect: Cleanse in order to destroy or prevent the growth of disease-carrying microorganisms.
Hydrogen peroxide is sometimes used in household first aid kits to clean and disinfect cuts and scrapes.
Resistance: When a bacteria is able to survive exposure to an antibiotic.
The bacteria that are not killed by the exposure to antiseptics or antibiotics survive to reproduce, producing an increasing population of bacteria with a resistance to those medications.
Naturally Acquired:
Memory cells left over from an infection
Antibodies passed from mother to fetus or infant
Artificially Acquired:
Active Immunity: Memory cells produced from a vaccine.
Passive Immunity: Antibodies injected into a person from an external source.
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