Biological Transport and Exchange Systems Flashcards

A set of vocabulary flashcards covering gas exchange, digestion, human circulation, and plant transport systems based on the lecture transcript.

Surface area to volume ratio

A measure of the surface area relative to size; larger organisms have a smaller ratio and require complex systems for oxygen and carbon dioxide exchange.

Lamelli

Structures in fish gills where blood flows in the opposite direction to water to maintain a steep concentration gradient for fast oxygen exchange.

Spiracles

Small tubes in insects through which oxygen moves into the body via diffusion or muscle contraction.

Trachea and tracheoles

A network of small tubes in insects that deliver oxygen directly to the cells where it is needed.

Stomata

Small openings in leaves through which gases are exchanged into the spongy mesophyll.

Spongy mesophyll

Leaf tissue with many air gaps providing a large surface area to volume ratio for gas diffusion.

C-rings of cartilage

Structures that hold the human trachea open to allow air to enter the lungs.

Alveoli

Numerous, small, lumpy air sacs in the lungs with a total surface area equivalent to the floor space of a small house and walls one cell thick.

Goblet cells

Cells in the airways that secrete mucus to trap dust and microbes.

Smooth muscle

Muscle in the bronchi and bronchioles that opens and closes the airways as necessary.

Spirometer

A device used to measure lung volume.

Vital capacity

The maximum volume of air that can be inhaled in a single breath.

Tidal volume

The volume of air moved in or out of the lungs per breath while at rest.

Residual volume

The volume of air that always remains in the lungs even after exhaling.

Digestion

The process of breaking down long molecules into shorter ones through hydrolysis facilitated by enzymes.

Bile

A substance that emulsifies lipids into droplets to increase the surface area for lipase enzymes to work on.

Proteases

Enzymes split into endopeptidases, exopeptidases, and dipeptidases used to break down proteins.

Ileum

The part of the small intestine where smaller molecules are absorbed via facilitated diffusion or co-transport.

Hemoglobin

A protein in red blood cells consisting of two beta chains and two alpha helices, each containing a heme group capable of carrying four oxygen molecules.

Affinity

The strength of the bond between hemoglobin and oxygen, which increases as the partial pressure of oxygen increases.

Dissociation curve

A graph showing how hemoglobin's oxygen saturation changes with partial pressure, demonstrating cooperative binding.

Fetal hemoglobin

A type of hemoglobin with a higher affinity for oxygen to ensure oxygen reaches the womb and placenta.

Double circulatory system

A system where blood enters the heart twice per cycle: once for the lungs and once for the rest of the body.

Sinoatrial node

The pacemaker cells of the heart that produce a voltage to cause the atria to contract.

Atrio-ventricular node

The node triggered after a delay that causes the ventricles to contract.

Diastole

The phase of the cardiac cycle when the atria and ventricles relax, allowing blood to enter the chambers.

Systole

The phase of the cardiac cycle when the heart chambers contract.

Tissue fluid

Liquid containing dissolved gases and nutrients forced out of capillaries by high hydrostatic pressure.

Xylem

Long, continuous tubes made of dead tissue that transport water and dissolved mineral ions upward from the roots.

Symplast pathway

The route of water movement through a plant between cells.

Apoplast pathway

The route of water movement through a plant between the root cell walls.

Transpiration

The process of water evaporating from the stomata, drawing water upward through the xylem via cohesion and capillary action.

Potometer

A device used to measure the rate of transpiration by tracking the movement of a water bubble.

Translocation

The transport of nutrient molecules like sucrose through the phloem, involving active loading and pressure gradients.

Phloem

Chains of living cells, including sieve tube elements and companion cells, responsible for the transport of sucrose.

Active loading

A type of co-transport involving hydrogen ions ($H^+$) and proteins that brings sucrose into companion cells.