Human Physiology Unit 3 Review Flashcards

Review Flashcards for Unit 3 Test

What is the main purpose of muscle in the body?

To produce force and contraction to cause movement

What are striated muscles?

Muscles that have a striped appearance under a microscope and include skeletal and cardiac muscles; they are voluntary

What are unstriated muscles?

Involuntary, smooth muscles (lacking stripes), and located in the walls of hollow internal organ

What are voluntary muscles?

Muscles that are under your conscious control, meaning you choose when to move them

What are thick filaments?

Microscopic rope-like structures found inside muscle cells that help muscles contract and move

What are thin filaments?

Tiny protein strands in muscle cells that help muscles contract and move

What are involuntary muscles?

Muscles that work automatically without you thinking about them

What are Skeletal Muscle Fibers?

Individual, long, thread-like muscle cells that make up the muscles attached to your skeleton

What do Skeletal Muscle Fibers do?

They contract (tighten) and relax to generate movement and maintain posture

What are Sarcomeres?

Smallest functional unit of striated muscle

What are A bands?

 Thick filaments along with portions of thin filaments that overlap

What are I Bands?

Remaining portion of thin filaments that do not project into A band

What is the Sarcoplasmic reticulum?

A specialized network of membranes found inside muscle cells that stores calcium ions

What is the Sarcolemma?

Cell membrane surrounding muscle fiber

What are Transverse tubules?

Narrow, tube-like inward extensions of the outer cell membrane (sarcolemma) found in skeletal and cardiac muscle cells

What are Cross-bridges?

The temporary physical connection formed when the head of a myosin protein molecule attaches to an actin protein filament inside a muscle cell

What forms thick filaments?

Myosin

What is the main structural component of thin filaments?

Actin

What is the Sliding filament mechanism?

How your muscles contract

• tiny protein fibers inside your muscle cells (actin and myosin) slide past each other to make the muscle shorter and stronger

What is the Power stroke?

 Stroking motion pulls the thin filament toward the center of the sarcomere

Why does the sarcoplasmic reticulum release calcium?

To trigger muscle contraction

What are Tendons?

A strong, flexible band of fibrous connective tissue that connects skeletal muscle to bone 

What is Flexion?

Contraction of sarcomeres Shortening of muscle

What is Extension?

Relaxation of sarcomeres Lengthening of muscle

What two primary factors can be adjusted to produce graded contractions?

• Number of muscle fibers contracting

• Tension developed by each contracting fiber

One motor neuron, plus all the muscle fibers it innervates, is known as a

Motor unit

What is Glycolysis?

The metabolic process that breaks down one molecule of glucose (a six-carbon sugar) into two molecules of pyruvate (three-carbon molecules) inside the cytoplasm of a cell; Produces 2 ATP

What is Oxidative phosphorylation?

The final stage of cellular respiration where cells use oxygen to turn nutrients into large amounts of chemical energy (ATP); Produces 28 ATP

What is Creatine phosphate?

A high-energy molecule stored in your muscles that acts as a rapid backup battery for energy 

What is Lactate production?

The cellular process where the enzyme lactate dehydrogenase converts pyruvate into lactate (the conjugate base of lactic acid) for energy without the use of oxygen

What is the Creatine Phosphate Pathway?

A metabolic pathway unique to muscle fibers and is the body's fastest system for producing immediate energy during short, intense bursts of exercise 

What is the Lactate Pathway/Cori Cycle?

A metabolic pathway that is unique to muscle fibers where lactate produced by the muscles during anaerobic (low-oxygen) exercise is transported through the blood to the liver, converted back into glucose, and sent back to the muscles for energy 

What are Slow-oxidative (Type I) fibers?

• Contract slowly and use aerobic (oxygen-based) respiration to produce energy

• High resistance to fatigue, producing low-power, sustained contractions ideal for posture and endurance activities like marathon running

What are Fast-oxidative (Type IIa) fibers?

• Contract relatively quickly and use a mix of aerobic and anaerobic metabolism

• Moderate resistance to fatigue, producing higher-tension contractions used for activities like walking or middle-distance running

What are Fast-glycolytic (Type IIx) fibers?

• Contract very quickly and rely primarily on anaerobic glycolysis (no oxygen required).

• Low resistance to fatigue, generating rapid, powerful, and high-tension bursts of energy used for sprinting and heavy weightlifting

What is Skeletal Muscle?

• Classification: Striated muscle, voluntary muscle

• Description: Bundles of long, thick, cylindrical, striated, contractile, multinucleate cells that extend the length of the muscle

• Typical location: Attached to bones of skeleton

• Function: Movement of body in relation to external environment

What is Cardiac Muscle?

• Classification: Striated muscle, involuntary muscle

• Description: Interlinked network of short, slender, cylindrical, striated, branched, contractile cells connected cell to cell by intercalated discs

• Location: Wall of heart

• Function: Pumping of blood out of heart

What is Smooth Muscle?

• Classification: Unstrained muscle, involuntary muscle

• Description: Loose network of short, slender, spindle- shaped, unstrained, contractile cells that are arranged in sheets

• Typical location: Walls of hollow organs and tubes, such as stomach and blood vessels

• Function: Movement of contents within hollow organs

What are key characteristics of smooth muscle?

Can still develop tensionyet inherently relaxes when stretched, slow and economical

What is the Circulatory system?

 Transport system of the body

What are the basic components of the Circulatory system?

• Heart: pump

• Blood vessels: passageways

• Blood: transport medium

What are the functions of the Circulatory System?

• Transportation (Oxygen, Nutrients, Waste, Hormones)

• Defense (White Blood Cells, Antibodies)

• Regulation (Temperature, pH, Osmotic Pressure)

What is Pulmonary circulation?

The movement of blood between the heart and lungs

What is Systemic circulation?

The movement of blood between the heart and all body systems?

What is the Atria?

The two upper chambers of the heart

What are the Ventricles?

The two lower chambers of the heart?

What are Atrioventricular valves?

One-way flaps located between the upper chambers (atria) and lower chambers (ventricles) of the heart that control blood flow and prevent backflow

What are Semilunar valves?

Pocket-like heart valves shaped like a half-moon and they control blood flow

What is the Cardiac Cycle?

The complete sequence of alternating contraction and relaxation of the heart chambers (atria and ventricles) that happens during a single heartbeat

What is the purpose of the Cardiac Cycle?

Pump oxygen-rich blood to the rest of the body and send oxygen-poor blood to the lungs in a continuous, coordinated rhythm

What is the Pericardium?

A thin, fluid-filled sac that surrounds and protects your heart

What is the Sinoatrial Node?

The heart's natural pacemaker, and it spontaneously generates electrical impulses that travel through the heart, causing it to contract and pump blood.

What are Purkinje fibers?

Specialized heart muscle cells that act as the heart's electrical wiring

What is Atrial excitation?

The process where an electrical signal starts in the heart's upper-right chamber (the sinoatrial or SA node) and spreads across the top two chambers of the heart (the atria)

What is Ventricular excitation?

The electrical signal spreading through the lower chambers of the heart (the ventricles), causing them to squeeze and pump blood to the lungs and the rest of the body

What is the Ventricular conduction system crucical for?

 Hastening spread of excitation in ventricles

What is an ECG (electrocardiogram)

A record of the overall spread of electrical activity through the heart

What are two normal heart sounds are associated with?

Valve closures

What does Cardiac Output depend on?

heart rate and stroke volume

How do you calculate Cardiac Output?

CO (Cardiac output) = HR (Heart Rate) x SV(Stroke Volume)

What is Intrinsic Control?

The ability of an organ, tissue, or cell to adjust its own function directly from the inside; without help from the nervous system or hormones

What is Extrinsic Control?

A physiological process where an organ or tissue is regulated by outside forces, specifically the nervous system or the endocrine (hormonal) system, rather than by the organ itself

How is blood transported to all parts of the body?

Through a system of vessels

To maintain homeostasis, what receive blood flow in excess of their needs?

reconditioning organs

What does blood flow through a vessel depend on?

The pressure gradient and vascular resistance

What is Flow Rate?

Volume of blood passing through per unit of time

What does F = ΔP/R mean?

Flow rate of blood through a vessel = pressure gradient/ resistance of blood vessels

What is the Pressure gradient in Blood Flow?

The difference in pressure between the beginning and end of a vessel

What is Resistance in Blood Flow?

Barrier to blood flow through a vessel

What is Viscosity?

Friction developed between molecules of a fluid as they slide over each other during fluid flow

What is the Vascular Tree?

The interconnected network of blood vessels that carries blood throughout your body

What are Arteries?

Blood vessels that carry blood away from the heart and out to the rest of the body

What is the Radius vessel?

One of the two main blood vessels in the forearm that ius small enough to offer considerable resistance to flow

What is Vasoconstriction?

The narrowing of blood vessels that happens when the smooth muscles in their walls tighten up

What is Vasodilation?

The widening of your blood vessels (arteries and veins) when the tiny muscles in their walls relax

What is Vascular tone?

The degree of constriction (tightness or squeeze) in the walls of a blood vessel compared to when it is fully relaxed

What is the local control of arteriolar radius important for?

 Determining the distribution of cardiac output

What does the local metabolic influence on arteriolar radius help with?

Matching blood flow with the organs’ needs

What are Capillaries?

Thin-walled vessels in which blood exchanges materials with the interstitial fluid between arteries and veins.

What is the main purpose of veins?

Carry oxygen-poor blood from your body's tissues back to your heart 

What is Venous Return?

The rate of blood flow returning from the body's veins back to the right side of the heart 

What is Blood Pressure?

The force of your blood pushing against the walls of your arteries as your heart pumps 

What causes Blood Pressure to go up or down?

What your body is doing (ex: physical activity), what you eat, and how you feel 

What is the baroreceptor reflex?

The body's automatic system that keeps your blood pressure stable

What are Baroreceptors?

Pressure sensors in the heart (atria and ventricles) and pulmonary/venous vessels 

What are some functions of the blood?

• Delivery of substances needed for cellular metabolism

• Removal of wastes

• Defense against microorganisms and injury

• Maintenance of acid-base balance

What is the Plasma of the blood?

the pale, yellowish liquid part of your blood that carries red blood cells, white blood cells, platelets, nutrients, hormones, and waste products

How much of the blood does the Plasma make up?

55% of the blood

What does the Plasma of the blood do?

• Transports essentials

• Removes waste

• Fights infections

• Helps blood clot

• Keeps body balanced

What is the hematocrit?

The percentage of your blood that is made up of red blood cells

What is the main purpose of the Erythrocytes (Red Blood Cells) of the blood?

O2 transport in the blood

How much of the blood for the Erythrocytes (Red Blood Cells) makeup of the blood?

45% of the blood

What is the role of hemoglobin with the red blood cells?

An iron rich protein in the red blood cells that carries oxygen from your lungs to the rest of your body and helps return carbon dioxide back to your lungs to be exhaled 

What continuously replaces worn-out erythrocytes?

The bone marrow

Erythropoiesis is controlled by what?

Erythropoietin from the kidneys

What is Primary polycythemia?

A rare, slow-growing blood cancer where the bone marrow makes too many red blood cells

What is Secondary polycythemia?

A condition where the body produces too many red blood cells because of another underlying health issue or external trigger, rather than a problem in the bone marrow

What is an Antigen?

Any substance, such as a protein, sugar, or chemical, that the immune system recognizes as foreign and uses to trigger a defense response

What is an Antibody?

Y-shaped protein made by your immune system to find and destroy harmful invaders like bacteria and viruses

What is Blood Type A’s Antigens on Erythrocytes and Antibodies in Plasma?

A; Anti-B