Heart Function and Blood Composition

Anatomy of the Heart: Composed of four chambers: left atrium, left ventricle, right atrium, right ventricle.
Function: Pumps blood throughout the body to supply oxygen and nutrients while removing waste.
Circulation Types:
- Systemic Circulation: Delivers oxygenated blood from the heart to the body.
- Pulmonary Circulation: Carries deoxygenated blood from the heart to the lungs for gas exchange.
Heart Cycle: Consists of systole (contraction) and diastole (relaxation).
Electrical Conduction: Regulated by the sinoatrial (SA) node, atrioventricular (AV) node, and Purkinje fibers.

Components:
- Plasma: Liquid portion (about 55% of blood); contains water, electrolytes, proteins, hormones, and waste products.
- Red Blood Cells (Erythrocytes): Carry oxygen via hemoglobin; unique biconcave shape increases surface area.
- White Blood Cells (Leukocytes): Part of the immune system; includes lymphocytes, neutrophils, etc.
- Platelets (Thrombocytes): Cell fragments involved in clotting.
Functions:
- Transportation of gases, nutrients, hormones, and waste.
- Regulation of body temperature, pH, and fluid balance.
- Protection against pathogens and blood loss.

Structure: Comprises lymph, lymph nodes, lymph vessels, and lymphoid organs (e.g., spleen, thymus).
Function:
- Returns excess interstitial fluid to the blood.
- Transports dietary lipids from the gastrointestinal tract.
- Facilitates immune responses by housing lymphocytes.
Lymph Flow: Moves through lymph vessels aided by muscle contractions and valves preventing backflow.

Components: Consists of arteries, veins, and capillaries.
Arteries: Carry oxygenated blood away from the heart (except pulmonary arteries).
Veins: Return deoxygenated blood to the heart (except pulmonary veins).
Capillaries: Microscopic vessels where nutrient and gas exchange occurs between blood and tissues.
Blood Pressure: Force exerted by circulating blood on vessel walls; regulated by heart rate, blood volume, and vessel elasticity.

Homeostasis: Maintenance of stable internal conditions, including fluid levels.
Regulatory Mechanisms:
- Kidneys: Filter blood to regulate fluid and electrolyte balance; produce urine.
- Hormones: Antidiuretic hormone (ADH) and aldosterone regulate water and sodium retention.
Imbalance Consequences: Dehydration (low fluid levels) vs. overhydration (excess fluid).
Indicators: Urine color, thirst, blood pressure, and electrolyte levels are key indicators of fluid balance.

Heart consists of four chambers: left atrium, left ventricle, right atrium, right ventricle.
Primary function is to pump blood, delivering oxygen and nutrients while removing metabolic waste.
Systemic Circulation: Oxygenated blood is distributed from the heart to the entire body.
Pulmonary Circulation: Deoxygenated blood is sent from the heart to the lungs for oxygenation.
Heart cycle includes two phases: systole (contraction) and diastole (relaxation).
Electrical conduction system involves:
- Sinoatrial (SA) node: initiates heartbeat.
- Atrioventricular (AV) node: transmits impulses to ventricles.
- Purkinje fibers: distribute impulses throughout the ventricles.

Blood is made up of several components:
- Plasma: Comprises about 55% of blood; contains water, electrolytes, proteins, hormones, and wastes.
- Red Blood Cells (Erythrocytes): Transport oxygen using hemoglobin; possess a biconcave shape for increased surface area.
- White Blood Cells (Leukocytes): Critical for immune defense; includes various types such as lymphocytes and neutrophils.
- Platelets (Thrombocytes): Cell fragments essential for blood clotting.
Blood functions include:
- Transportation of gases, nutrients, and hormones.
- Regulation of temperature, pH levels, and fluid homeostasis.
- Protection against infections and blood loss.

Lymphatic system includes components like lymph, lymph nodes, lymph vessels, and lymphoid organs (e.g., spleen and thymus).
Functions of the lymphatic system:
- Returns excess interstitial fluid to circulation.
- Transports dietary lipids from the digestive system to bloodstream.
- Supports immune responses by housing and activating lymphocytes.
Lymph flow is enhanced by muscle contractions and one-way valves that prevent backflow.

Vascular system composed of arteries, veins, and capillaries.
Arteries: Transport oxygen-rich blood away from the heart, with the exception of pulmonary arteries.
Veins: Carry deoxygenated blood back to the heart, except for pulmonary veins that carry oxygenated blood.
Capillaries: Microscopic vessels where gas and nutrient exchange occurs with tissues.
Blood Pressure: Represents the force exerted by blood on vessel walls; influenced by heart rate, blood volume, and the elasticity of blood vessels.

Homeostasis is crucial for maintaining stable internal fluid levels within the body.
Regulatory Mechanisms include:
- Kidneys: Filter blood to manage fluid and electrolyte balance; urine production is a result.
- Hormones: Antidiuretic hormone (ADH) and aldosterone play key roles in regulating water and sodium retention.
Consequences of imbalances:
- Dehydration occurs with low fluid levels; overhydration arises from excess fluid intake.
Key indicators of fluid balance include urine color, thirst level, blood pressure, and electrolyte concentrations.