Human Respiration, Gas Exchange, and Blood

Comprehensive vocabulary flashcards covering the human respiratory system, cellular aerobic respiration, blood components, gas exchange, and immune responses against pathogens.

Pathogens

Microorganisms, such as certain bacteria and viruses, that can get into the body and cause illness.

Antibodies

Y-shaped chemicals produced by certain white blood cells that target specific pathogens, either killing them directly or gluing them together so other white blood cells can destroy them.

White blood cell defense mechanisms

The processes by which white blood cells defend the body, either by pushing out cytoplasm 'fingers' to capture and digest pathogens, or by releasing antibodies to neutralize them.

Blood plasma

The pale yellow liquid portion of blood in which blood cells float, transporting dissolved substances around the body.

Red blood cells (erythrocytes)

Cells specialized for transporting oxygen that lack a nucleus and mitochondria, containing haemoglobin and numbering at least $20\text{ trillion}$ in an adult body (about $5\text{ million}$ per $1\,\text{cm}^3$ of blood).

Haemoglobin

A red, iron-containing protein pigment found inside red blood cells that combines with oxygen to carry it to respiring tissues, giving blood its red appearance.

Oxyhaemoglobin

A bright red chemical compound formed inside red blood cells when haemoglobin binds with oxygen in the lungs.

Oxygen transport cycle

The pathway in which oxygen diffuses from lung alveoli into capillary blood, binds to haemoglobin, travels to respiring body cells, and leaves deoxygenated blood to return to the lungs.

Glucose

A type of sugar produced by the digestive breakdown of carbohydrates that acts as an energy store and is transported in the blood to provide fuel for cellular respiration.

Mitochondria

Tiny intracellular structures where aerobic respiration takes place, releasing energy from glucose in a controlled manner to meet the cell's requirements.

Aerobic respiration

A chemical reaction inside mitochondria that uses oxygen to break down glucose and release energy, represented by the word equation: $\text{glucose} + \text{oxygen} \rightarrow \text{carbon dioxide} + \text{water}$.

Heat production in respiration

The release of thermal energy that occurs when chemical energy in glucose is transferred during cellular respiration, causing actively respiring cells and tissues to become warmer than their surroundings.

Diffusion (gas exchange)

The net movement of gas particles from an area of higher concentration to an area of lower concentration, such as oxygen moving from alveoli into blood and carbon dioxide moving from blood into alveoli.

Air sacs (alveoli)

Microscopic, thin-walled pockets in the lungs surrounded by dense capillary networks where oxygen diffuses into the blood and carbon dioxide diffuses out.

Trachea

The windpipe through which inhaled and exhaled air travels between the throat and the bronchi, kept permanently open by rings of cartilage.

Cartilage rings

Strong, supportive structures encircling the trachea and bronchi that prevent the airways from collapsing during breathing.

Bronchi

The two primary branches of the trachea (singular: bronchus), supported by cartilage, that carry air into each lung.

Bronchioles

The smaller branching tubes that divide from the bronchi and distribute air deep into the lungs to the air sacs.

Inhalation (breathing in)

The process where intercostal muscles contract (pulling ribs up and out) and the diaphragm contracts (moving down), increasing chest volume, lowering internal pressure, and drawing air in.

Exhalation (breathing out)

The process where intercostal muscles relax (ribs drop down) and the diaphragm relaxes into a domed shape, decreasing chest volume, raising internal pressure, and squeezing air out.

Intercostal muscles

Muscles situated between the ribs that contract and relax to alter the volume and pressure of the chest cavity during ventilation.

Diaphragm

A sheet of muscle located beneath the lungs that flattens downwards upon contraction during inhalation and returns to its domed resting shape upon relaxation during exhalation.