Human Physiology: The Study of Body Function

Vocabulary flashcards covering the introductory concepts of human physiology, scientific methodology, homeostasis, feedback control systems, and primary tissue classifications based on Chapter 1 of the Fox and Rompolski lecture notes.

Physiology

The study of biological function; it concerns the normal function of cells to the organism as a whole, emphasizing mechanisms and cause-and-effect sequences derived from scientific experiments.

Pathophysiology

A field that focuses on how disease or injury affects physiological processes, which also aids in the understanding of normal biological functions.

Comparative physiology

The study of the differences and similarities in the functions of invertebrates and vertebrates, which has assisted in the development of pharmaceutical drugs.

Hypothesis

A testable explanation formulated from observations in the scientific method.

In vitro

Research conducted on cells outside of a living organism, typically in a culture dish.

In vivo

Research conducted within a living creature, such as studies done in rats and mice to observe chemical effects and toxic side effects.

Phase I clinical trials

Experimental trials that test a drug on healthy human volunteers to evaluate side effects, rates of passage, and dosage.

Phase II clinical trials

Experimental trials conducted to test the effectiveness of a drug on people who have the particular disease the drug is intended to treat.

Phase III clinical trials

Large-scale trials involving both sexes, many age groups, ethnicities, and people with multiple health conditions; successful completion allows for FDA approval.

Phase IV clinical trials

Trials conducted to test other potential applications for a drug after it has been approved for sale.

Aristotle

A Greek thinker (384 to 322 BC) who speculated about body function but did not perform experimental work.

William Harvey

An English physician (1578 to 1657) who demonstrated that the heart pumps through a closed system of vessels.

Claude Bernard

A French scientist (1813 to 1878) who observed that the internal environment (milieu intérieur) remains relatively constant despite external changes.

Walter Cannon

A U.S. scientist who in 1932 coined the term homeostasis to describe the internal consistency of the body.

Homeostasis

The constancy of the internal environment; maintaining this state is the main purpose of physiological mechanisms, and deviation from it indicates disease.

Negative feedback loop

A continuous process that maintains homeostasis by moving in the opposite direction from a change, making the deviation from a set point smaller or reversing it.

Receptors

Sensors in the body that detect changes and send information to an integrating center.

Integrating center

A component in a feedback loop that assesses change around a set point and sends instructions to an effector.

Effector

Muscles or glands that make adjustments to counter a change from the set point in a negative feedback loop.

Antagonistic effectors

Opposing effectors that move conditions in opposite directions to maintain dynamic constancy, such as sweating when hot and shivering when cold.

Dynamic constancy

Maintaining physiological conditions within a certain normal range through antagonistic reactions.

Arterial pH normal range

$7.35$ to $7.45$

Fasting blood glucose normal range

$70$ to $99\,mg/100\,ml$

Positive feedback

A process where the end product stimulates the process and amplifies the changes that stimulated the effectors, such as during blood clotting or uterine contractions in childbirth.

Intrinsic regulation

Regulation of processes within an organ where cells within that organ sense a change and signal neighboring cells to respond.

Extrinsic regulation

Regulation of an organ by the brain or other organs using the endocrine or nervous system.

Hormones

Regulatory molecules secreted into the blood by the endocrine system to be transported to target organs.

Primary tissues

The four major categories of tissues that compose organs: muscle, nervous, epithelial, and connective tissue.

Skeletal muscle

Voluntary, striated muscle tissue formed by the union of myoblasts into myofibers (syncytium); primarily associated with bones.

Cardiac muscle

Involuntary, striated muscle found only in the heart with branched, interconnected fibers and specialized connections called intercalated discs.

Smooth muscle

Involuntary, non-striated muscle found in the walls of hollow organs like the digestive tract and blood vessels.

Peristalsis

Coordinated, wave-like contractions of smooth muscle layers to move substances through organs.

Neurons

Nerve cells that conduct impulses; they consist of dendrites (receivers), an axon (sender), and a cell body (metabolic center).

Neuroglia

Supporting cells in the nervous system that do not conduct impulses but are essential for neuron function.

Simple epithelium

A single layer of epithelial cells specialized for the transport of substances.

Stratified epithelium

Epithelial tissue composed of multiple layers, primarily providing protection.

Exocrine glands

Glands derived from epithelial tissues that transport secretions through ducts to body surfaces or into hollow organs.

Endocrine glands

Glands derived from epithelial tissues that lack ducts and secrete hormones directly into capillaries.

Connective tissue proper

A category of connective tissue composed of protein fibers and gel-like ground substance, including loose, dense regular, adipose, and dense irregular subtypes.

Chondrocytes

Specialized cells found in cartilage surrounded by a semi-solid ground substance.

Osteoblasts

Cells that trap mineral salts to form concentric layers of calcified bone material.

Osteocytes

Mature bone cells that live within spaces called lacunae once the bone matrix has hardened.

Totipotent

A characteristic of zygotes meaning the cells can become any type of cell in the body; these are true stem cells.

Multipotent

Adult stem cells that are limited to a narrow range of possibilities but can become several related cells (e.g., bone marrow cells).

Pluripotent

Embryonic stem cells that have the ability to form any type of unrelated cells.

Intracellular compartment

The area inside cells containing $65\%$ of total body water.

Extracellular compartment

The area outside cells, which includes blood plasma and interstitial fluid.