Biology: Differentiation, Homeostasis, Body Fluids, and Feedback

Vocabulary flashcards covering key terms and concepts from differentiation, homeostasis, body fluids, and feedback mechanisms discussed in the lecture.

Zygote

A fertilized egg; the single initial cell from which all future cells differentiate.

Differentiation

The process by which unspecialized cells become specialized in structure and function.

Osteoprogenitor cell

A bone precursor cell that differentiates into osteoblasts during bone development.

Osteoblast

Bone-forming cell that differentiates from osteoprogenitor cells.

Osteocyte

A mature bone cell formed when osteoblasts become embedded in bone matrix.

Responsiveness

The ability of living things to detect and respond to changes in the internal or external environment.

Reproduction

Production of offspring; in the body, cells reproduce by mitosis (somatic) or meiosis (gametes).

Mitosis

Cell division that produces two identical somatic daughter cells.

Meiosis

Cell division producing sex cells (gametes) with half the chromosome number.

Homeostasis

Stable, dynamic internal environment maintained by regulatory processes; disruption leads to illness.

Negative feedback

A control system that reverses a change to restore homeostasis (the response counteracts the stimulus).

Positive feedback

A control system that reinforces the initial change, amplifying it until a terminating event occurs (e.g., labor, lactation).

Receptors

Sensors that detect changes in the internal or external environment and relay information to the control center.

Control center

The brain or endocrine system that processes sensory information and directs responses.

Effectors

Organs or tissues that execute responses to restore homeostasis.

Thermoreceptors

Receptors that detect temperature changes in the skin and hypothalamus.

Hypothalamus

Brain region that acts as a primary regulator for temperature and other homeostatic processes; coordinates responses via nervous and endocrine systems.

Vasodilation

Widening of blood vessels that increases blood flow to the skin and promotes heat loss.

Vasoconstriction

Narrowing of blood vessels that reduces heat loss and can raise blood pressure.

Normal body temperature

Approximately 37 degrees Celsius (98.6 degrees Fahrenheit).

Blood glucose normal range

Approximately 70 to 110 milligrams per deciliter (mg/dL).

Atmospheric pressure

Normal atmospheric pressure is 1 atmosphere (1 atm) = 760 mmHg.

Millimeters of mercury (mmHg)

Unit used to measure pressure, including blood and atmospheric pressure.

Water in the body

The most abundant substance; ~60% of body weight; medium for metabolic reactions and transport; heat conductor.

Total body water (TBW)

About 60% of body weight; divided into intracellular and extracellular compartments.

Intracellular fluid (ICF)

Fluid inside cells; about 70% of TBW.

Extracellular fluid (ECF)

Fluid outside cells; about 30% of TBW; includes interstitial, intravascular, and transcellular fluids.

Interstitial fluid

Fluid in the spaces between cells; part of the extracellular fluid.

Intravascular fluid

Fluid within blood vessels (blood plasma) and lymph; part of the extracellular fluid.

Transcellular fluid

Specialized extracellular fluids such as cerebrospinal fluid (CSF), synovial fluid, aqueous humor, and serous fluids.

CSF (cerebrospinal fluid)

Transcellular fluid surrounding brain and spinal cord; essential for protection and nourishment.

Synovial fluid

Transcellular fluid found in joints; lubricates joints.

Aqueous humor

Transcellular fluid in the eye; maintains intraocular pressure.

Serous fluid

Transcellular fluid in body cavities (pleural, pericardial, peritoneal) that provides lubrication.

Intracellular vs extracellular compartments

Intracellular: within cells (ICF); Extracellular: outside cells (ECF, includes interstitial, intravascular, and transcellular fluids).

Oxygen

Essential for cellular respiration; humans can survive only a few minutes without external oxygen.

Food (nutrients)

Raw materials for energy and growth; digested molecules used by cells for energy, maintenance, and repair.

Oxytocin

Hormone from the posterior pituitary; stimulates uterine contractions and milk ejection during breastfeeding.

Amniotic fluid

Fluid surrounding the fetus in the amniotic sac; rupture of the sac (water breaking) initiates labor.

Labor (positive feedback)

A positive feedback loop where cervical stretch triggers oxytocin release, increasing contractions until birth ends the cycle.

Milk ejection reflex

Breastfeeding stimulus triggers oxytocin release, causing contraction of breast smooth muscle and milk expulsion.