B3.2 Transport Theme: Form and Function Level of Organization : Organisms

Capillaries

Small blood vessels that connect arteries to veins, facilitating the exchange of materials between the blood and cells.

Adaptations of Capillaries

They have a large surface area, narrow lumen, and thin walls to allow rapid diffusion of materials.

Narrow Lumen

The small diameter of capillaries, allowing only one red blood cell to pass through at a time.

Thin Walls of Capillaries

Capillary walls are typically one cell thick, which aids in the rapid exchange of materials by diffusion.

Arteries

Blood vessels that transport blood away from the heart, characterized by thick walls and narrow lumen.

Thick Wall of Arteries

Adaptation of arteries to withstand and maintain high blood pressure.

Collagen in Arteries

Strengthens the outer wall of the artery, allowing it to withstand high blood pressure.

Smooth Muscle in Arteries

Contracts to maintain blood pressure between heartbeats.

Elastic Fibers in Arteries

Allow arteries to stretch and recoil, helping to keep blood moving.

Narrow Lumen of Arteries

Helps maintain high blood pressure in the arteries.

Pulse Rate Measurement

Pulse can be measured at the radial artery in the wrist or the carotid artery in the neck.

Veins

Blood vessels that return blood to the heart, characterized by thin walls and wide lumen.

Adaptations of Veins

Thin walls that allow compression by skeletal muscles and a wide lumen for carrying large volumes of blood.

Atherosclerosis

Hardening and narrowing of arteries due to buildup of cholesterol and other substances.

Occlusion of Coronary Arteries

Blockage of coronary arteries that can lead to heart tissue death and heart attacks.

Causes of Atherosclerosis

Damage to artery linings due to high blood pressure, leading to cholesterol plaque buildup.

Risk Factors of Atherosclerosis

Obesity, physical inactivity, smoking, and a high-fat diet increase the risk.

Correlation Coefficient

Indicates the relationship between two variables; close to zero suggests no relationship.

Saturated Fats and Coronary Heart Disease

Increased saturated fat intake correlates with higher deaths from coronary heart disease.

Transpiration

Movement of water up the plant and its evaporation from the leaves.

Role of Xylem

Transports water and dissolved minerals from roots to leaves.

Xylem Adaptations

Thickened walls, long hollow tubes, and no end walls for efficient water transport.

Dicotyledonous Stem

Contains epidermis, cortex, and vascular bundles for support and nutrient transport.

Capillary Action

Water movement through xylem by hydrogen bonds and adhesive properties.

Tissue Fluid

Surrounds cells, enabling material exchange between blood and cells.

Reuptake of Tissue Fluid

Most tissue fluid returns to the blood by osmosis due to oncotic pressure.

Drainage of Tissue Fluid

Excess tissue fluid is taken up by lymph ducts; called lymph.

Lymph Vessels

Adapted with thin walls, gaps for fluid entry, and valves to prevent backflow.

Single Circulation

Bony fish have a two-chambered heart; blood passes through the heart only once.

Double Circulation

Mammals have a four-chambered heart; blood is pumped to lungs and then to the body.

Cardiac Cycle Stages

Includes systole (contraction) and diastole (relaxation) of heart muscles.

Pacemaker (Sinoatrial Node)

Controls the rate of heartbeat in the heart.

Root Pressure

Created by active transport of minerals into roots, moving water up the xylem.

Translocation

The movement of nutrients through the phloem from sources to sinks.

Phloem Tissue Composition

Composed of companion cells and sieve tubes for nutrient transport.

Sieve Tubes Adaptations

Reduced cytoplasm, no nucleus, and sieve plates for efficient nutrient flow.

Companion Cells Function

Provide metabolic support for sieve tube element cells in phloem.

Source and Sink in Translocation

The source produces or stores nutrients, while the sink uses or stores them.

Fluid Flow in Phloem

Water moves into phloem from xylem, increasing hydrostatic pressure for sap transport.

Metabolism of Cells

Uses nutrients and oxygen, producing metabolic wastes that diffuse into tissue fluid.

Oncotic Pressure

The pressure exerted by plasma proteins, promoting the re-uptake of tissue fluid.

Blood Plasma Components

Includes dissolved nutrients, oxygen, metabolic wastes, and white blood cells.