MACH2.-muscles, immune/lymphatic/cardiovascular

Skeletal muscle

• attached to bones

• voluntary

• striated

• body movement, posture, and joint stability

Smooth muscle

• in walls of hollow organs (stomach, intestines, blood vessels) and in the iris of the eye

• involuntary

• controls internal movements like digestion, breathing, and circulation

Cardiac muscle

• in the heart

• involuntary

• contracts rhythmically to pump blood throughout the body; cross-fibered structure allows coordinated contraction.

Functions of muscles

• movement: voluntary and involuntary actions

• posture and balance

• circulation

• heat production: muscle activity generates heat, helping maintain body temperature

Tendons

• tough cords of connective tissue that attach muscles to bones

• help transfer the force of muscle contraction to create movement

Ligaments

work with muscles to stabilize joints and prevent excessive movement

Role of lymphatic and immune system

• work together to protect the body from infection, illness, and disease

• transport network for immune cells and helps remove waste, toxins, and excess fluid from tissues

Lymph nodes

• small, bean-shaped glands located in the neck, armpits, and groin

• filter lymph fluid, trapping bacteria and viruses

• produce and store lymphocytes and macrophages that destroy harmful substances

Lymph nodules

• small masses of lymph tissue that are not enclosed by a capsule

• contain lymphocytes and macrophages that help fight infections

Thymus

• located behind the sternum

• large in children, shrinks with age

• produces and matures T-cells, a type of white blood cell critical for immune defense

Spleen

• largest lymph organ

• upper-left side of the abdomen

• filters blood, removes old red blood cells, and houses immune cells that detect and destroy pathogens

Interstitial Fluid (Lymph)

• fluid found between cells; becomes lymph once collected into lymphatic vessels

• transports immune cells and waste products through the lymphatic system

How does the immune system work?

defends the body by recognizing and responding to antigens—foreign substances such as bacteria, viruses, or toxins.

Antigen

A foreign substance that triggers an immune response

Antibody

A protein made by the immune system to target and neutralize specific antigens

B cells

Recognize antigens and produce antibodies that help destroy invaders

T cells

Attack and destroy infected or abnormal cells directly

Monocytes

Large white blood cells that engulf and destroy pathogens marked by antibodies

Naturally acquired immunity

• developing antibodies after recovering from an illness

• long-term

Artificially Acquired Active Immunity

• Receiving a vaccination that stimulates antibody production

• long-term

Naturally Acquired Passive Immunity

• Passing antibodies from mother to baby through the placenta or breast milk

• short-term

Artificially Acquired Passive Immunity

• Receiving ready-made antibodies (e.g., immune globulin after exposure)

• short-term

What is the cardiovascular system responsible for?

transporting blood, oxygen, nutrients, and waste throughout the body

What makes up the cardiovascular system?

• heart

• blood vessels

• blood

Heart

• a muscular organ located in the chest (mediastinum)

• pumps blood throughout the body to deliver oxygen and remove waste

Arteries/arterioles

• thick-walled vessels that carry blood away from the heart

• propel oxygenated blood to the body

• arterioles are smaller branches of arteries

Veins/venules

• thin-walled vessels that carry blood toward the heart

• transport deoxygenated blood

• contain valves to prevent backflow

Capillaries

• Microscopic vessels connecting arteries and veins

• Allow exchange of oxygen, nutrients, and waste between blood and body tissues

Endocardium

• Inner lining of the heart chambers and valves

• Smooth surface to reduce friction and protect tissue

Myocardium

• Thick, muscular middle layer of the heart

• Responsible for the pumping action of the heart

Pericardium

• Outer protective membrane around the heart

• Reduces friction and protects the heart from surrounding organs

Right atrium

Receives deoxygenated blood from the body via the superior and inferior vena cava

Right ventricle

Pumps blood through the pulmonary valve to the lungs via the pulmonary artery for oxygen exchange

Left atrium

Receives oxygenated blood from the lungs through the pulmonary veins (the only veins that carry oxygenated blood)

Left ventricle

Pumps oxygenated blood through the aortic valve into the aorta, sending it throughout the body

Heart valves

ensure that blood flows in one direction and prevent backflow

• tricuspid

• pulmonary

• mitral (bicuspid)

• aortic

Pulmonary circulation

Moves blood between the heart and lungs to exchange carbon dioxide for oxygen

Systemic circulation

Moves oxygenated blood from the heart to the body and returns deoxygenated blood back to the heart

Hearts electrical system/ cardiac cycle

1. The Sinoatrial (SA) Node, known as the pacemaker, spontaneously generates the electrical impulse

2. The electrical wave sweeps across the two upper chambers , causing the atria to squeeze and push blood down into the lower chambers

3. The impulse travels to the Atrioventricular (AV) Node, which delays it slightly to allow the atria to contract

4. it continues from the AV node to the Bundle of His and bundle branches down the ventricular septum

5. Finally, it spreads to the Purkinje fibers, causing the ventricles to contract and pump blood.

How often does the cardiac cycle repeat?

repeats about 60–80 times per minute at rest