Untitled Flashcards Set

How many muscles does the human body have?

Over 600 muscles.

What are the three types of muscles?

Smooth muscle, cardiac muscle, and skeletal muscle.

What happens during muscle contraction?

Muscles squeeze (flex).

What happens during muscle relaxation?

Muscles return to a relaxed state.

What is cardiac muscle?

An involuntary muscle of the heart that makes it beat, found only in the heart.

What controls cardiac muscle?

The autonomic nervous system.

What is smooth muscle?

Involuntary muscle found lining organs such as the stomach, walls of blood vessels, and esophagus.

What is skeletal muscle?

Voluntary muscle that makes the bones of the skeleton move.

What connects skeletal muscles to bones?

Tendons.

What are antagonistic muscles?

Pairs of muscles that work against each other to move a joint (e.g., biceps and triceps).

What is the function of flexors?

Contracts to bend a joint.

What is the function of extensors?

Contracts to straighten a joint.

How much energy is lost as heat during skeletal muscle contraction?

80%.

What is a sarcolemma?

A delicate sheath that surrounds muscle fibers.

What are myofilaments?

Threads of contractile proteins within muscle fibers.

What defines the length of a muscle fiber?

Z lines that anchor the actin filaments.

What starts muscle contraction?

A nerve impulse and the release of calcium.

What is the role of calcium in muscle contraction?

Binds with troponin, freeing the myosin binding site.

What is required to reset myosin?

ATP.

What causes muscle fatigue?

Accumulation of lactic acid due to insufficient ATP supply.

What is creatine phosphate?

A compound that helps regenerate ATP in muscle cells.

What is breathing?

The exchange of air between the lungs and the environment.

What is respiration?

All processes involved in the exchange of oxygen and carbon dioxide, including breathing, gas exchange, and cellular respiration.

What is the respiratory membrane?

The site where oxygen and gases diffuse between the body and the environment.

What do tiny hairs in nasal cavities do?

Filter, warm, and moisten incoming air.

What is the trachea?

The windpipe.

What are bronchi?

Passages from the trachea to the lungs.

What are bronchioles?

Smallest passageways in the respiratory system.

What are alveoli?

Air sacs where gas exchange occurs.

What is the diaphragm?

A muscle that separates the thoracic cavity from the abdominal cavity and assists in breathing.

How is oxygen transported in the blood?

By hemoglobin, forming oxyhemoglobin.

How is carbon dioxide transported?

9% in plasma, 27% as carbaminohemoglobin, 64% as carbonic acid.

What is carbonic anhydrase?

An enzyme that speeds the conversion of CO2 and water to carbonic acid.

What is bronchitis?

Inflammation of the bronchial tubes due to infections or environmental irritants.

What is emphysema?

A disorder where alveoli are overinflated.

What is asthma?

A condition characterized by reversible narrowing of bronchial passages.

What is a negative feedback loop?

A biological response that slows or stops a reaction.

What determines muscle contraction speed?

Isomers of myosin (Type I, IIa, IIx).

What is the latent period?

The pause between a nerve impulse and muscle contraction.

What do intercostal muscles do?

Raise and lower the rib cage during breathing.

What do chemoreceptors detect?

Low O2 levels, high CO2 levels, and increased H+ concentration.

What are the carotid and aortic bodies?

Specialized receptors that detect low oxygen levels.