Biology Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering important biological terms and concepts.

ammonia

A small, toxic molecule (NH3) produced by nitrogen fixation or as a metabolic waste product of protein and nucleic acid metabolism.

anatomy

The structure of an organism.

anterior pituitary

A portion of the pituitary that develops from non-neural tissue; consists of endocrine cells that synthesize and secrete several tropic and nontropic hormones.

antidiuretic hormone (ADH)

A peptide hormone, also known as vasopressin, that promotes water retention by the kidneys.

aquaporin

A channel protein in the plasma membrane of a plant, animal, or microorganism cell that facilitates osmosis, the diffusion of free water across the membrane.

Bowman’s capsule

A cup-shaped receptacle in the vertebrate kidney that is the initial, expanded segment of the nephron where filtrate enters from the blood.

collecting duct

The location in the kidney where processed filtrate, called urine, is collected from the renal tubules.

conformer

An animal for which an internal condition conforms to changes in an environmental variable.

connective tissue

Animal tissue that functions mainly to bind and support other tissues, having a sparse population of cells scattered through an extracellular matrix.

control center

The component of a feedback system that compares sensor inputs with the set point for a regulated variable and alters the activity of an effector if necessary.

countercurrent exchange

The exchange of a substance or heat between two fluids flowing in opposite directions.

distal tubule

In the vertebrate kidney, the portion of a nephron that helps refine filtrate and empties it into a collecting duct.

ectothermic

Referring to organisms for which external sources provide most of the heat for temperature regulation.

effector

1) A pathogen-encoded protein that cripples a plant’s innate immune system. 2) The component of a feedback system that causes a change in the regulated variable.

endocrine gland

A gland that secretes hormones directly into the interstitial fluid, from which they diffuse into the bloodstream.

endocrine system

The internal system of communication involving hormones, ductless glands that secrete hormones, and molecular receptors on or in target cells.

endothermic

Referring to organisms that are warmed by heat generated by their own metabolism.

epinephrine

A catecholamine that mediates stress responses; also known as adrenaline.

epithelial tissue

Sheets of tightly packed cells that line organs and body cavities.

excretion

The disposal of nitrogen-containing metabolites and other waste products.

exocrine gland

A gland that secretes hormones through a duct onto a body surface or into a body cavity.

filtrate

Cell-free fluid extracted from the body fluid by the excretory system.

filtration

The extraction of water and small solutes from the body fluid in excretory systems.

glial cells

Non-neuronal cells of the nervous system that support and nourish neurons.

glomerulus

A ball of capillaries surrounded by Bowman’s capsule in the nephron, serving as the site of filtration.

gradient

A difference in a particular quality between two regions.

homeostasis

The steady-state physiological condition of the body.

hormones

Secreted chemicals formed in specialized cells that travel in body fluids and act on target cells.

hypothalamus

The ventral part of the vertebrate forebrain that functions in maintaining homeostasis.

interstitial fluid

The fluid filling the spaces between cells in most animals.

kidney

One of a pair of excretory organs where blood filtrate is formed and processed into urine.

loop of Henle

The hairpin turn in the nephron involved in water and salt reabsorption.

muscle tissue

Tissue consisting of long muscle cells that can contract.

negative feedback

A form of regulation in which accumulation of an end product slows the process.

nephron

The tubular excretory unit of the vertebrate kidney.

nervous system

The fast-acting internal system of communication involving sensory receptors and nerve cells.

nervous tissue

Tissue made up of neurons and supportive cells.

neurons

A nerve cell; the fundamental unit of the nervous system.

organ

A specialized center of body function composed of several different types of tissues.

organ system

A group of organs that work together in performing vital body functions.

osmoconformer

An animal that is isoosmotic with its environment.

osmolarity

Solute concentration expressed as molarity.

osmoregulation

Regulation of solute concentrations and water balance by a cell or organism.

osmoregulator

An animal that controls its internal osmolarity independent of the external environment.

oxytocin

A hormone that induces contractions of the uterine muscles during labor.

pancreas

A gland with exocrine and endocrine tissues; involved in digestion and homeostasis.

peritubular capillaries

Tiny blood vessels surrounding the proximal and distal tubules in the kidney.

physiology

The processes and functions of an organism.

pituitary gland

An endocrine gland at the base of the hypothalamus that produces and secretes many hormones.

positive feedback

A form of regulation in which an end product speeds up that process.

posterior pituitary

An extension of the hypothalamus composed of nervous tissue that secretes certain hormones.

proximal tubule

The portion of a nephron that conveys and helps refine filtrate.

reabsorption

The recovery of solutes and water from filtrate in excretory systems.

regulator

An animal that moderates internal changes in the face of external fluctuations.

renal pelvis

The funnel-shaped chamber that receives processed filtrate from the kidney's collecting ducts.

response

In feedback regulation, a physiological activity triggered by a change in a variable.

secretion

The discharge of molecules synthesized by a cell.

sensor

In homeostasis, a receptor that detects a stimulus.

set point

A value maintained for a particular variable, such as body temperature.

stimulus

A fluctuation in a variable that triggers a response in feedback regulation.

thermoregulation

The maintenance of internal body temperature within a tolerable range.

tissue

An integrated group of cells with a common structure and function.

transport epithelia

Layers of specialized epithelial cells that carry out and regulate solute movement.

urea

A soluble nitrogenous waste produced in the liver.

ureter

A duct leading from the kidney to the urinary bladder.

urethra

A tube that releases urine from the mammalian body.

uric acid

A product of protein metabolism and a major nitrogenous waste product of certain animals.

urinary bladder

The pouch where urine is stored prior to elimination.

vasopressin

Another name for antidiuretic hormone (ADH).