Unit III: Homeostasis and Selected Body Systems

A collection of vocabulary flashcards covering homeostasis, the circulatory, immune, and reproductive systems based on the Unit III Student Guide.

Homeostasis

The process by which animals regulate their internal environment to maintain a steady state within a narrow range of internal conditions.

Chemical barriers

These involve specific proteins or chemicals that prevent pathogens.

Example: stomach acid, kills most bacteria ingested through food and lysozyme.

Lysozyme

An enzyme found in tears and saliva that breaks down bacteria. Because the eyes and mouth are exposed openings, lysozyme act as a preventive measure to keep pathogens from reaching deeper parts of the body.

Innate immunity overview

This is the immediate, nonspecific response to anything recognized as nonself (pollen, grass, dog fur)

Macrophages

These cells circulate in the blood and look for anything no self. Their primary action is phagocytic: they “eat” or consume the invading entity

Neutrophils

These are also phagocytic cells found in the blood. They are specifically specialized to find bacteria.

Negative feedback loop

The most common method of maintaining homeostasis where the body responds to a deviation from a set point by working to return the system to that set point.

Positive feedback loop

A strategy to maintain homeostasis that does not stop and keeps going in response to a stimulus, eventually resulting in a return to normal, such as during childbirth.

Hemoglobin

A protein in red blood cells that transports oxygen picked up in the lungs and delivers it to tissues; it consists of four polypeptides with four spots where oxygen attaches to iron seats.

Platelets

Cellular fragments involved in clotting blood through the interaction of blood proteins like fibrinogen, fibrin, prothrombin, and thrombin.

Arteries

Thick-walled blood vessels that function to carry blood away from the heart.

Capillaries

Tiny, thin-walled vessels where the exchange of gases, nutrients, and waste occurs between the blood and tissues.

Veins

Blood vessels that carry blood back to the heart and contain valves to prevent the backflow of blood.

Systolic pressure

The higher number in a blood pressure reading that measures the pressure in the arteries when the heart beats.

Diastolic pressure

The lower number in a blood pressure reading that measures the pressure in the arteries when the heart rests between beats.

Hypertension

A condition characterized by blood pressure above a certain threshold that can cause variety of health problems.

Lymphatic system

A series of vessels carrying a fluid called lymph that functions in recycling excess interstitial fluid back to the bloodstream and fighting illness.

Sinoatrial (SA) node

The pacemaker of the heart located in the right atrium that generates electrical signals to trigger heartbeats without nerve stimulation.

Pulmonary circuit

The pathway where deoxygenated blood is pumped from the right side of the heart to the lungs to become oxygenated again.

Systemic circuit

The pathway where oxygenated blood from the lungs enters the left side of the heart and circulates to the tissues and organs of the body.

Atherosclerosis

A condition characterized by the buildup of plaque, including fatty deposits and cholesterol, in the arterial walls, leading to narrowed arteries.

Arteriosclerosis

The thickening and stiffening of the arterial wall, which reduces blood flow and elasticity.

High-density lipoprotein (HDL)

Known as "good cholesterol," it helps remove excess cholesterol from the bloodstream and transport it to the liver for excretion.

Low-density lipoprotein (LDL)

Known as "bad cholesterol," it contributes to the formation of plaque in the arteries when present in excess.

Stent

A small mesh-like tube made of metal or fabric inserted into an artery to keep it open and improve blood flow.

Specific defenses

Also known as adaptive immunity, it is a targeted response targeting only the pathogen that triggered it based on memory developed over time.

Antigens

Substances, typically proteins or parts of pathogens, that trigger an immune response.

Antibodies

Proteins produced by B cells that bind to specific antigens to help neutralize, precipitate, or clump pathogens for removal.

Agglutination

A process where antibodies bind to multiple pathogens at once, clumping them together to facilitate removal by immune cells.

Active Immunity

Occurs when the body produces its own antibodies and memory cells in response to an antigen, typically providing long-lasting protection.

Passive Immunity

Immediate but temporary protection provided when antibodies are transferred from one individual to another, such as through the placenta or via injection.

Autoimmune Disorders

Conditions occurring when the immune system mistakenly fails to recognize the body's own cells as "self" and attacks its own tissues.

Allergies

An overreaction of the immune system to a harmless substance known as an allergen, involving the production of IgE antibodies and the release of histamines.

Acrosome

A cap-like structure on the head of a sperm containing enzymes necessary for penetrating the outer layers of an egg.

Capacitation

A series of physiological changes sperm undergo in the female reproductive tract to gain the ability to fertilize an egg.

Gonadotropin-Releasing Hormone (GnRH)

A hormone produced by the hypothalamus that starts the chain reaction leading to testosterone production and spermatogenesis.

Follicle-Stimulating Hormone (FSH)

In males, it promotes sperm production; in females, it stimulates the growth and maturation of ovarian follicles and the production of estrogen.

Luteinizing Hormone (LH)

In males, it stimulates testosterone production; in females, a surge triggers ovulation and promotes the formation of the corpus luteum.

Testosterone

The primary male sex hormone responsible for sperm production and the development of secondary sexual characteristics.

Estrogen

A female hormone produced by follicles that stimulates the thickening of the endometrial lining and secondary sexual characteristics.

Progesterone

Known as the hormone of pregnancy, it is produced by the corpus luteum to maintain the endometrial lining and prevent uterine contractions.

Corpus luteum

The structure formed from the remnants of a follicle after ovulation that secretes progesterone to prepare the body for potential pregnancy.

Endometrium

The inner lining of the uterus that thickens in preparation for implantation and is shed during menstruation if no pregnancy occurs.

Human chorionic gonadotropin (hCG)

A hormone secreted by the placenta after an embryo implants in the uterine lining; it is the hormone detected by pregnancy tests.

Infertility

The inability to conceive after $1\,\text{year}$ of regular, unprotected intercourse.

Chlamydia

An STD caused by the bacterium Chlamydia Trachomatis, often asymptomatic but treatable with antibiotics.

Gonorrhea

An STD caused by the bacterium neisseria Gonorrhoeae, which can lead to Pelvic Inflammatory Disease (PID) if left untreated.

Syphilis

An STD caused by the bacterium treponema Pallidum that progresses in stages and is primarily treated with antibiotics.

Antigens

Substances, typically proteins or parts of pathogens, that trigger an immune response.

Antibodies

Proteins produced by B cells that bind to specific antigens to help neutralize, precipitate, or clump pathogens for removal.

Pathogen

An organism that causes disease, including viruses, bacteria, fungi, and parasites.