B3.2 Transport Practice Flashcards

This set of vocabulary flashcards covers transport mechanisms in both humans and plants, including blood vessel adaptations, cardiac physiology, and xylem/phloem transport systems as outlined in the B3.2 syllabus.

Continuous capillaries

The most common type of capillary, found in almost all vascularized tissues, characterized by a complete endothelial lining and tight junctions.

Fenestrated capillaries

Capillaries containing pores in the endothelial lining that make them permeable to larger molecules; common in the small intestine and kidneys.

Sinusoid capillaries

The least common type of capillary, which are flattened with extensive intercellular gaps and incomplete basement membranes, allowing the passage of the largest molecules and cells.

Auscultation

A diagnostic measurement involving listening to the internal sounds of body organs, such as heart valve closures, using a stethoscope.

Systolic pressure

The higher blood pressure value representing the pressure in the vessel when the heart is contracting.

Diastolic pressure

The lower blood pressure value representing the pressure in the vessel when the heart is relaxing.

Sphygmomanometer

A blood pressure cuff used to measure pressure in the arteries by cutting off and slowly releasing circulation.

Normal adult blood pressure

Approximately $120/80\,mmHg$.

Coronary arteries

Blood vessels that surround and nourish the cardiac tissue with oxygen and nutrients.

Atherosclerosis

The hardening and narrowing of the arteries due to the deposition of cholesterol.

Atheromas

Fatty deposits that develop in the arteries and significantly reduce the diameter of the lumen, known as stenosis.

Thrombus

A blood clot formed when an atherosclerotic plaque ruptures, restricting blood flow.

Embolus

A dislodged thrombus that travels through the blood and can cause a blockage in a smaller arteriole.

Transpiration

The loss of water from a plant through the stomata by evaporation.

Cohesion tension theory

The theory that water is pulled up the xylem due to negative pressure generated by transpiration and the cohesive properties of water molecules via H-bonds.

Lignin

A substance that impregnates and thickens xylem vessel walls, strengthening them to prevent collapse.

Pits

Gaps in the lignified walls of xylem vessels through which water can enter and exit.

Cambium

A tissue in the vascular bundles of dicotyledonous plants responsible for the production of more xylem and phloem.

Tissue fluid

A watery substance formed from leaked blood plasma that bathes the cells of tissues and facilitates the exchange of substances.

Lymph

The name for tissue fluid once it has entered the narrow, blind-ended vessels of the lymphatic system.

Single Circulatory System

A simple loop where blood flows from Heart to Gills to Body and back to the Heart, typical of bony fish.

Double Circulatory System

A system where blood flows through two loops: the Pulmonary Circuit (to the lungs) and the Systemic Circuit (to the body), typical of mammals.

Myogenic contraction

The ability of cardiac muscle cells to contract without stimulation from the central nervous system.

Sinoatrial node (SA node)

A cluster of cells in the upper right atrium acting as the primary pacemaker by generating electrical impulses to set the heart's rhythm.

Atrioventricular node (AV node)

A node located in the cardiac skeleton that propagates electrical signals slowly to create a delay between atrial and ventricular contractions.

Septum

A thick muscular wall that divides the heart's left and right sides, preventing the mixing of oxygenated and deoxygenated blood.

Diastole

A relatively long recovery period after heart contraction where the heart is insensitive to stimulation and passively refills with blood.

Root pressure

Positive pressure potential in the xylem generated by the active transport of mineral ions into the roots, followed by the osmotic entry of water.

Guttation

The appearance of tiny water droplets on the edges of leaves caused by root pressure pushing water out of hydathodes.

Sieve tube elements

Phloem cells with a distinctive design and porous sieve plates that facilitate the unhindered flow of organic nutrients.

Companion cells

Phloem cells that coordinate the transport of sap and provide ATP from their abundant mitochondria for active loading and unloading.

Source

The region of a plant where organic nutrients are produced, such as a leaf cell.

Sink

The region of a plant where organic nutrients are utilized or stored, such as root cells or growing shoots.