Biology: Gas Exchange, Circulatory, and Muscle Systems Overview

Gas Exchange

The process of exchanging oxygen and carbon dioxide between an organism and its environment

Diffusion

Movement of particles from an area of high concentration to low concentration

Surface Area to Volume Ratio

Measurement showing how much surface area an organism has compared to its volume

Why small organisms rely on diffusion

They have a high surface area to volume ratio

Gas exchange surface

A thin moist surface where oxygen and carbon dioxide diffuse

Alveoli

Tiny air sacs in lungs where gas exchange occurs

Function of alveoli

Increase surface area and allow efficient diffusion of oxygen into blood

Features of efficient gas exchange surfaces

Large surface area, thin membrane, moist surface, good blood supply

Ventilation

Process of moving air into and out of lungs

Inhalation

Diaphragm contracts and chest cavity expands pulling air into lungs

Exhalation

Diaphragm relaxes and air is pushed out of lungs

Hemoglobin

Protein in red blood cells that carries oxygen

Oxyhemoglobin

Hemoglobin bound to oxygen

Transport system

System that moves substances such as oxygen, nutrients, and wastes around the body

Circulatory system

Heart, blood, and blood vessels working together to transport materials

Arteries

Blood vessels carrying blood away from the heart

Veins

Blood vessels carrying blood back to the heart

Capillaries

Tiny blood vessels where exchange of gases and nutrients occurs

Double circulation

System where blood passes through the heart twice per cycle

Pulmonary circulation

Blood flow between heart and lungs

Systemic circulation

Blood flow between heart and body tissues

Cardiac muscle

Muscle tissue that makes up the heart

Myoglobin

Oxygen-binding protein found in muscle cells

Muscle contraction

Process where muscle fibers shorten to produce movement

Sarcomere

Basic contractile unit of muscle fibers

Actin

Thin filament protein in muscle

Myosin

Thick filament protein responsible for muscle contraction

Sliding filament theory

Actin and myosin slide past each other to shorten the muscle

ATP in muscles

Provides energy for muscle contraction

Motor neuron

Nerve cell that stimulates muscle contraction

Motility

Ability of organisms or cells to move

Cilia

Hair-like structures that move substances across cell surfaces

Flagella

Long tail-like structure used for movement in some cells