Cardiovascular, Lymphatic, and Respiratory Systems: Study Guide (Chapters 11-13)

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Cardiovascular System

Anatomy of the Heart

The heart is a muscular organ responsible for pumping blood throughout the body. It is enclosed by several layers, including the pericardium.

Coverings of the Heart: The heart is surrounded by the pericardium, which consists of the fibrous pericardium and the serous pericardium. The visceral layer of the serous pericardium is also known as the epicardium.
Walls of the Heart: The heart wall has three layers: epicardium (outer), myocardium (middle, muscular), and endocardium (inner).
Valves: The heart contains four valves: tricuspid (right atrioventricular), bicuspid/mitral (left atrioventricular), pulmonary (right semilunar), and aortic (left semilunar).

Example: The epicardium is the visceral layer of the serous pericardium.

Pathway of Blood Through the Heart

Blood flows through the heart in a specific sequence, alternating between oxygenated and deoxygenated states.

Pulmonary Circulation: Deoxygenated blood travels from the right ventricle to the lungs via the pulmonary arteries, returns oxygenated via pulmonary veins to the left atrium.
Systemic Circulation: Oxygenated blood is pumped from the left ventricle through the aorta to the body, returns deoxygenated to the right atrium via the venae cavae.
Oxygenated vs. Deoxygenated Blood: Right side handles deoxygenated blood; left side handles oxygenated blood.

Heart Valves: Location and Function

Valves ensure unidirectional blood flow and open/close in response to pressure changes during the cardiac cycle.

Systole: Ventricular contraction; AV valves close, semilunar valves open.
Diastole: Ventricular relaxation; AV valves open, semilunar valves close.

Intrinsic Conduction System

The heart's electrical system coordinates contraction.

Nodes: Sinoatrial (SA) node (right atrium), Atrioventricular (AV) node (junction of atria and ventricles), AV bundle, bundle branches, Purkinje fibers.
Impulse Pathway: SA node → AV node → AV bundle → bundle branches → Purkinje fibers.

Cardiac Cycle and Heart Sounds

The cardiac cycle includes all events associated with blood flow through the heart.

Heart Sounds: "Lub" (AV valves close), "Dub" (semilunar valves close).
Valves During Systole/Diastole: See above.

Cardiac Output

Cardiac output (CO) is the amount of blood pumped by the heart per minute.

Variables: Heart rate (HR) and stroke volume (SV).
Formula:

Stroke Volume: The volume of blood ejected by a ventricle in one contraction.

Systemic Circulation Pathway

Blood travels from the left ventricle through the aorta, branching to all body tissues, and returns via veins to the right atrium.

Electrocardiogram (ECG) Waves

An ECG records the electrical activity of the heart.

P wave: Atrial depolarization
QRS complex: Ventricular depolarization
T wave: Ventricular repolarization

Factors Modifying Heart Rate

Autonomic nervous system (sympathetic/parasympathetic)
Hormones (e.g., epinephrine)
Physical activity
Body temperature

Major Arteries of Systemic Circulation

Abdominal Aorta: Branches include celiac trunk, superior mesenteric, renal, inferior mesenteric, and common iliac arteries.

Hepatic Portal Circulation

Blood from digestive organs passes through the liver before entering systemic circulation.

Blood Pressure and Peripheral Resistance

Blood Pressure: The force of blood against vessel walls.
Peripheral Resistance: Resistance to blood flow in vessels, affected by vessel diameter, blood viscosity, and vessel length.

Fluid Movements at Capillary Beds

Exchange of nutrients, gases, and wastes occurs via diffusion, filtration, and osmosis.

Lymphatic System and Body Defenses

Lymphatic Vessels and Ducts

The lymphatic system returns excess tissue fluid to the bloodstream and provides immune defense.

Thoracic Duct: Drains lymph from most of the body.
Right Lymphatic Duct: Drains lymph from right upper limb, right side of head and thorax.

Return of Lymph Towards the Heart

Valves in lymph vessels
Skeletal muscle contraction
Breathing movements

Other Lymphoid Organs

Lymph nodes: Filter lymph
Spleen: Filters blood, destroys old RBCs
Thymus: Matures T cells
Tonsils: Protect against pathogens entering the throat

MALT (Mucosa-Associated Lymphoid Tissue)

Includes tonsils, Peyer's patches, and appendix

Lines of Defense

First Line: Skin, mucous membranes
Second Line: Phagocytes, inflammation, fever
Third Line: Adaptive immunity (B and T cells)

Adaptive Defense System

Humoral Immunity: B cells produce antibodies
Cellular Immunity: T cells attack infected cells

Inflammation and Diapedesis

Inflammatory Response: Redness, heat, swelling, pain
Diapedesis: Movement of WBCs out of capillaries into tissues

Complement Fixation and MAC

Complement: Proteins that enhance immune response
MAC (Membrane Attack Complex): Forms pores in pathogen membranes

Interferons

Proteins released by virus-infected cells to inhibit viral replication

Humoral Immunity

B cells produce antibodies
Plasma cells secrete antibodies

T Lymphocytes and APCs

T cells: Attack infected cells
APCs (Antigen-Presenting Cells): Present antigens to T cells

Active and Passive Humoral Immunity

Type	Source	Example
Active Natural	Exposure to pathogen	Infection
Active Artificial	Vaccination	Flu shot
Passive Natural	Maternal antibodies	Breast milk
Passive Artificial	Injection of antibodies	Antivenom

Antibodies: Structure and Function

Y-shaped proteins
Bind to antigens to neutralize or mark for destruction

Immune Responses: Key Terms

Chemotaxis: Movement of cells toward chemical signals
Agglutination: Clumping of cells
Complement Fixation: Activation of complement proteins
Neutralization: Blocking harmful effects of antigens
Precipitation: Soluble antigens become insoluble

Disorders of Immunity

Autoimmune diseases
Allergies
Immunodeficiency

Respiratory System

Functions of Respiratory Passageways, Goblet Cells, and Tonsils

Respiratory Passageways: Conduct air, filter, warm, and moisten
Goblet Cells: Produce mucus to trap particles
Tonsils: Immune defense

Pathway of Air Through the Respiratory System

Nose → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli

Cilia of Smokers

Cilia are damaged, reducing ability to clear mucus and debris

Anatomy of the Lungs

Right lung: 3 lobes; left lung: 2 lobes
Alveoli: Site of gas exchange

Respiratory Membrane and Gas Exchange

Formed by alveolar and capillary walls
Gas exchange by diffusion

Respiratory Physiology: Four Phases

Pulmonary Ventilation: Breathing in and out
External Respiration: Gas exchange between lungs and blood
Transport of Gases: Blood carries O2 and CO2
Internal Respiration: Gas exchange between blood and tissues

Inspiration and Expiration

Inspiration: Diaphragm and external intercostals contract, thoracic volume increases, pressure decreases, air enters
Expiration: Muscles relax, thoracic volume decreases, pressure increases, air exits

Respiratory Volumes and Capacities

Volume/Capacity	Description
Tidal Volume (TV)	Amount of air inhaled/exhaled in one breath
Inspiratory Reserve Volume (IRV)	Extra air inhaled after normal inspiration
Expiratory Reserve Volume (ERV)	Extra air exhaled after normal expiration
Residual Volume (RV)	Air remaining after maximal exhalation
Vital Capacity (VC)	TV + IRV + ERV

Gas Transport in the Blood

O2 carried by hemoglobin
CO2 transported as bicarbonate, dissolved in plasma, or bound to hemoglobin

Control of Respiration

Medulla and pons regulate breathing
CO2 levels are primary stimulus

Respiratory Disorders

Atelectasis: Collapse of lung
Pneumothorax: Air in pleural cavity causing lung collapse

Developmental Aspects of the Respiratory System

Lung development and maturation
Surfactant production in infants

Additional info: Academic context and definitions were added to clarify brief study guide points and ensure completeness.