Human Body Systems, Homeostasis, and Chemistry of Life

Flashcards based on lecture notes covering human organ systems, homeostatic feedback loops, body gradients, cell communication methods, and foundational chemistry principles.

Urinary System

A body system consisting of the kidneys, ureters, urinary bladder, and urethra that removes metabolic wastes from the blood, regulates fluid, electrolyte, and acid-base balance, and stimulates blood cell production.

Male Reproductive System

A body system consisting of the prostate gland, ductus deferens, testis, and penis that produces and transports sperm, secretes hormones, and carries out sexual function.

Female Reproductive System

A body system consisting of mammary glands, uterine tube, ovary, uterus, and vagina that produces and transports eggs, serves as the site of fetal development, fetal nourishment, childbirth, and lactation, secretes hormones, and carries out sexual function.

Homeostasis

The maintenance of the body's internal environment through the coordination of many variables controlled to set points to prevent homeostatic imbalances.

Feedback Loops

Mechanisms that control homeostatic processes by responding to changes in a regulated variable, which can be negative or positive.

Negative Feedback Loop

A homeostatic mechanism where a change of a variable in one direction results in a change in the opposite direction, opposing the initial change and reducing output to return the variable to normal range.

Positive Feedback Loop

A control mechanism where an effector reinforces and increases the initial stimulus, often found within a negative feedback loop to produce a faster response until an end point is reached.

Stimulus

An event that occurs when a regulated variable falls outside its normal homeostatic range.

Receptor

A cellular structure that detects information when a regulated variable is outside normal range and sends that information to a control center.

Control Center

A structure that receives information from a cellular receptor and sends signals to effectors.

Effector

Cells or organs that receive signals from a control center and cause a response that returns a variable to normal homeostatic ranges or increases the initial stimulus.

Blood Clot Formation

A positive feedback process where an injured blood vessel causes platelets to stimulate other platelets to form a clot, resulting in the overall negative feedback effect of stopping bleeding.

Childbirth Mechanism

A positive feedback process where the head of the fetus pushes the cervix, transmitting nerve impulses to the brain to stimulate the pituitary gland to secrete oxytocin, which stimulates uterine contractions.

Gradient

A condition present any time more of something exists in one area than another when the two areas are connected.

Concentration Gradient

A condition present where there is a difference in concentration or amount of a substance between two connected regions or areas.

Pressure Gradient

A condition present where there is a difference in pressure between two connected regions or areas.

Electrical Gradient

A condition present where there is a difference in charge ($+\text{ or }-$) between two connected regions or areas.

Hormones

Chemicals released into interstitial fluid and blood capillaries, transported through veins to the heart and through arteries to capillary beds, where they bind to receptors on target cells.

Neurotransmitters

Chemical messengers released by a nerve cell into the space near a muscle cell to trigger a response in the muscle cell.

Electrical Signals (Cell Communication)

Intercellular communication involving the movement of charged particles called ions between cells.

Matter

Anything that has mass and occupies space, existing as a solid, liquid, or gas.

Mass

The amount of matter in a living or non-living object.

Chemistry

The study of matter and its interactions.

Atom

The smallest unit of matter that retains original elemental properties, composed of protons, neutrons, and electrons.

Protons ($p^+$)

Positively charged ($+\text{ charge}$) subatomic particles located in an atom's centrally located nucleus, having a relatively large mass of approximately $1.0073\,\text{amu}$.

Neutrons ($n^0$)

Subatomic particles with a neutral charge ($0$) located inside an atom's nucleus.

Electrons ($e^-$)

Negatively charged ($-\text{ charge}$) subatomic particles located outside an atom's nucleus in electron shells, representing the smallest of the subatomic particles.