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Blood, Heart, Blood Vessels, Lymphatic, Immune, and Endocrine Systems: Study Guide

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Blood: Components and Functions

Formed Elements, Proteins, and Non-Proteins in Blood

The blood is a specialized connective tissue composed of cellular elements and plasma. It serves as the main transport medium for nutrients, gases, wastes, and hormones.

  • Formed Elements: These are the cellular components of blood, including:

    • Erythrocytes (Red Blood Cells): Transport oxygen and carbon dioxide.

    • Leukocytes (White Blood Cells): Defend against infection and disease.

    • Platelets (Thrombocytes): Involved in blood clotting.

  • Proteins: Major plasma proteins include:

    • Albumin: Maintains osmotic pressure and transports substances.

    • Globulins: Include antibodies and transport proteins.

    • Fibrinogen: Essential for blood clotting.

  • Non-Proteins: These include electrolytes, nutrients (glucose, amino acids), gases (O2, CO2), and waste products (urea, creatinine).

Hematocrit

The hematocrit is the percentage of blood volume occupied by red blood cells. It is a key indicator of blood health and oxygen-carrying capacity.

  • Normal Values: Approximately 45% in males, 40% in females.

  • Measurement: Determined by centrifuging blood and measuring the proportion of RBCs.

  • Formula:

Blood Cell Production (Hematopoiesis)

Blood cells are produced in the bone marrow through a process called hematopoiesis.

  • Stem Cells: All blood cells originate from hematopoietic stem cells.

  • Erythropoiesis: Formation of red blood cells, stimulated by erythropoietin.

  • Leukopoiesis: Formation of white blood cells.

  • Thrombopoiesis: Formation of platelets from megakaryocytes.

Plasma vs. Serum

  • Plasma: The liquid portion of blood containing proteins, electrolytes, and other solutes.

  • Serum: Plasma without clotting factors (fibrinogen).

  • Comparison Table:

Component

Plasma

Serum

Clotting Factors

Present

Absent

Proteins

Albumin, Globulins, Fibrinogen

Albumin, Globulins

Use

Transfusions, diagnostics

Diagnostics, research

The Heart: Anatomy and Physiology

Layers, Chambers, Valves, and Vessels

The heart is a muscular organ with four chambers and several layers, valves, and associated vessels.

  • Layers:

    • Epicardium: Outer layer (visceral pericardium).

    • Myocardium: Middle, muscular layer responsible for contraction.

    • Endocardium: Inner lining of the heart chambers.

  • Chambers: Right atrium, right ventricle, left atrium, left ventricle.

  • Valves: Tricuspid, pulmonary, mitral (bicuspid), aortic.

  • Vessels: Superior/inferior vena cava, pulmonary arteries/veins, aorta.

Cardiac Conduction System

The heart's electrical system coordinates contraction.

  • Sinoatrial (SA) Node: Pacemaker, initiates impulse.

  • Atrioventricular (AV) Node: Delays impulse.

  • Bundle of His: Conducts impulse to ventricles.

  • Purkinje Fibers: Distribute impulse throughout ventricles.

Blood Flow Through the Heart

  • Deoxygenated blood enters right atrium → right ventricle → pulmonary arteries → lungs.

  • Oxygenated blood returns via pulmonary veins → left atrium → left ventricle → aorta → body.

Myocardium Repair

  • Damaged myocardium is repaired by formation of scar tissue (fibrosis), not regeneration.

  • Limited regenerative capacity due to lack of stem cells.

Pericardium and Its Layers

  • Pericardium: Double-walled sac surrounding the heart.

  • Layers:

    • Fibrous Pericardium: Outer, tough layer.

    • Serous Pericardium: Inner, subdivided into parietal and visceral layers.

Blood Vessels

Vasa Vasorum

  • Vasa Vasorum: Small blood vessels that supply the walls of large arteries and veins.

Conducting and Distributing Arteries

  • Conducting Arteries: Large elastic arteries (e.g., aorta, pulmonary trunk).

  • Distributing Arteries: Medium-sized muscular arteries (e.g., femoral, radial).

Vein Draining Blood from the Head

  • Jugular Vein: Main vessel draining blood from the head.

Types of Blood Capillaries

  • Continuous Capillaries: Most common, found in muscles, skin, CNS; tight junctions.

  • Fenestrated Capillaries: Have pores; found in kidneys, intestines, endocrine glands.

  • Sinusoidal Capillaries: Large gaps; found in liver, spleen, bone marrow.

Type

Structure

Location

Function

Continuous

Tight junctions

Muscle, skin, CNS

Restricts passage

Fenestrated

Pores

Kidney, intestine

Permits filtration

Sinusoidal

Large gaps

Liver, spleen

Allows cell passage

Lymphatic and Immune Systems

Lymphatic Vessels and Collecting Vessels

  • Lymphatic Capillaries: Small, blind-ended vessels collecting interstitial fluid.

  • Collecting Vessels: Larger vessels with valves, similar to veins.

  • Trunks: Major lymphatic trunks include jugular, subclavian, bronchomediastinal, lumbar, and intestinal.

Cells Involved in Immune Response

  • Lymphocytes: B cells (produce antibodies), T cells (cell-mediated immunity).

  • Macrophages: Phagocytosis and antigen presentation.

  • Dendritic Cells: Antigen-presenting cells.

Antigens, Epitopes, and Haptens

  • Antigen: Substance that triggers an immune response.

  • Epitope: Specific region of an antigen recognized by antibodies.

  • Hapten: Small molecule that becomes antigenic when attached to a carrier.

Antibody Structure and Producing Cells

  • Antibody: Y-shaped protein with variable and constant regions.

  • Produced by: Plasma cells (differentiated B cells).

Endocrine System

Definition of Hormone

  • Hormone: Chemical messenger secreted by endocrine glands, transported by blood to target organs.

Major Endocrine Glands, Hormones, and Actions

  • Pituitary (Hypophysis): Secretes GH, ACTH, TSH, LH, FSH, prolactin, ADH, oxytocin.

  • Thyroid: Secretes thyroxine (T4), triiodothyronine (T3), calcitonin.

  • Adrenal: Secretes cortisol, aldosterone, epinephrine.

  • Pancreas: Secretes insulin, glucagon.

  • Parathyroid: Secretes parathyroid hormone (PTH).

Hypophysis (Pituitary Gland) and Its Hormones

  • Anterior Pituitary: GH, ACTH, TSH, LH, FSH, prolactin.

  • Posterior Pituitary: ADH, oxytocin (produced in hypothalamus, released by posterior pituitary).

Diabetes Mellitus Types and Hormone Involved

  • Type 1 Diabetes: Autoimmune destruction of beta cells; lack of insulin.

  • Type 2 Diabetes: Insulin resistance; relative insulin deficiency.

  • Hormone: Insulin.

Growth Hormone (GH) Disorders

  • Overproduction: Acromegaly (adults), gigantism (children).

  • Underproduction: Dwarfism.

Example: In acromegaly, excess GH causes abnormal growth of bones and tissues in adults.

Additional info: The study guide covers key concepts from chapters 18 (Blood), 19 (Heart), 20 (Blood Vessels), 21 (Lymphatic and Immune Systems), and 17 (Endocrine System) of a typical ANP college course.

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