CARDIOVASCULAR SYSTEM: BLOOD, THE HEART Human Anatomy Unit 4
CARDIOVASCULAR SYSTEM: BLOOD, THE HEART
Human Anatomy
Unit 4
Components
• Cardiovascular system – Heart – Blood vessels – Blood – transport of nutrients,
hormones, oxygen, waste, carbon dioxide
• Lympha@c system (*) – Lympha@cs – lymph – Lymph nodes – Lymph organs – Immunity, transports lipids,
maintains @ssue fluid balance
The Cardiovascular system and Lympha@c
system work in tandem
Hematology
• Study of blood and components • Composi@on of Blood – Plasma
• ≈ 55% total volume
– Formed elements • ≈ 45% total volume • Erythrocytes • Leukocytes • Thrombocytes (Platelets)
Plasma
• Predominately water ≈ 92% • Plasma proteins • Major solutes
– Salts – Minerals – Bicarbonate buffer
• Transported substances – Gases – Sugars, amino acids, vitamins – Hormones – Waste products……etc.
Plasma Proteins
• Predominately made in liver • Major plasma proteins – Albumins
– Lipoproteins – CloXng Factors – Globulins
• Including an@bodies – Gamma globulins
– Made by lymphocytes
Formed Elements
Thrombocytes
• Formed by disintegra@on of megakaryocytes
• Released into plasma • Last 3‐5 days • Important in blood cloXng
Erythroctes (RBC)
• Red blood cells • Anucleate • Lack mitochondria • Millions of hemoglobin molecules
• Life span = 3‐4 months
Hemoglobin
• Quaternary protein produced by red blood cells
• Contains 4 iron (Fe) containing pep@des that bind oxygen
Erythrocyte Development
• Develop from erythroblasts • Synthesize hemoglobin un@l 1/3 full
• Then lose nucleus and mitochondria
Pluripotent (more than one outcome) stem cells can give rise to any fetal or adult cell in the body
Leukocytes
• Granular – Neutrophils – Eosinophils – Basophils
• Agranular – Monocytes (macrophage) – Lymphocytes
• T‐cells • B‐cells • NK cells
Neutrophils (PMN’s)
• First WBC at an infec@on site
• 50‐60% of circula@ng leukocytes
• Voracious phagocytes • Ahack microbes
Eosinophils
• Slightly phagocy@c • Effec@ve against helminths
• Allergic and hypersensi@vity reac@ons
• Contribute to chronic inflamma@on
Basophils
• Mature into mast cells of loose connec@ve @ssue
• Produce: – Heparin – Histamine
• Inflamma@on, especially related to allergies
Monocytes
• Become macrophage when ac@vated
• Eat microbes cellular debris
• An@gen Presen@ng Cells (APC) – link nonspecific body defenses to the immune response
Lymphocytes
• Primary cells of the lympha@c system
• Responsible for specific immunity – T cells – B cells – NK cells
Leukocyte Development
The Heart
• 4 chambers – Atria (atrium, singular)
– Ventricles • Valves
– Atrioventricular – Semilunar
• Creates pressure to pump blood through 2 circuits – Pulmonary
– Systemic
Circuits of Blood Flow
Structures of the Heart Wall
• Pericardium – Visceral pericardium – Serous membrane – Suppor@ng layer of areolar CT
• Myocardium – Layers of cardiac muscle
@ssue – CT, blood vessels, nerves
• Endocardium – Simple squamous epithelium – Con@nuous with mesothelium
of blood vessels
Cardiac Muscle Tissue
• Striated • Branched • Interdigitated • Centrally located nucleus • Intercalated discs • Fibrous skeleton
– Collagen, elas@n – Stabilizes cells – Provides support to valves – Distributes force of
contrac@on
Superficial Anatomy of the Heart
Superficial Anatomy of the Heart
Superficial Anatomy of the Heart
Internal Anatomy of the Heart
Atria
• Thin wall • Receiving chambers • Derived from veins • Auricles
– folded extensions of the atria
– increase volume • Pec@nate muscle
– atrial muscle, “honeycomb” appearance
Ventricles
• Thick wall • Pumping chambers • Derived from arteries • Trabeculae = “crossbars of
flesh” • R ventricle
– thinner wall – pumps to lungs – moderator bands control the
volume of the RV
• L ventricle – 2‐3 X’s thicker than the RV – pumps to systemic circuit
Relaxed Ventricles
Contrac@ng Ventricles
Coronary Blood Vessels
Coronary Blood Vessels
Fetal Heart