Download Circulatory System

Honors Biology
Heart
•Approximately the size of your fist
•Weighs less than a pound
•5 Liters of blood is pumped through 60 000 miles
of blood vessels per minute
•Beats ~100 000 times a day
Heart Covering
Pericardium
• Protects and anchors heart
• Prevents overfilling
Heart Wall
Epicardium - visceral layer of the serous pericardium
Myocardium – cardiac muscle layer forming the bulk of the
heart
Endocardium – lines the heart chambers and continues with
endothelial lining of blood vessels
External Heart: Major Vessels of the Heart
•Superior & inferior venae cava
•Right and left pulmonary veins
•Pulmonary trunk (splits into right & left pulmonary arteries)
•Ascending aorta (3 branches) – brachiocephalic, carotid, &
subclavian arteries
Atria of the Heart
•Atria are the receiving chambers of the heart
•Blood enters right atria from superior & inferior venae cava &
coronary sinus
Blood enters left atria from pulmonary veins
Ventricles of the Heart
• Ventricles are the discharging chambers
• Papillary muscles mark ventricular walls
• Interventricular septum separate ventricles
Right ventricle pumps blood into the pulmonary trunk
Left ventricle pumps blood into the aorta
Pathway of Blood through the Heart and
Lungs (Pulmonary & Systemic Circuits)
Pulmonary Circuit
•
Right atrium  tricuspid valve  right ventricle
•
Right ventricle  pulmonary semilunar valve  pulmonary
arteries lungs
Systemic Circuit
•
Lungs  pulmonary veins  left atrium
•
Left atrium  bicuspid valve  left ventricle
•
Left ventricle  aortic semilunar valve  aorta
•
Aorta  systemic circulation
Microscopic Heart Muscle Anatomy
•
Cardiac muscle is striated, short, fat, branched, and
interconnected
•
Intercalated discs anchor cardiac cells together & allow
free passage of ions
•
Heart muscle behaves as a functional syncytium
Cardiac Cycle
Cardiac cycle refers to all events associated with blood flow
through the heart
The cardiac cycle has two phases:
Systole (contraction)
Diastole (relaxation)
Cardiac Conduction
Electrocardiography (ECG or EKG)
Electrical activity is recorded by electrocardiogram (EKG)
P wave corresponds to depolarization of SA node & atria
(ATRIAL SYSTOLE)
QRS complex corresponds to ventricular depolarization
(VENTRICULAR SYSTOLE & ATRIAL DIASTOLE)
T wave corresponds to ventricular repolarization
(VENTRICULAR DIASTOLE)
Atrial repolarization record is masked by the larger QRS
complex
Abnormal ECG Deflection Wave Patterns
Sinus Bradycardia
Rate = 40-59 b.p.m.
Sinus Tachycardia
Rate = 101-160 b.p.m.
Causes
•CHF, hypoxia, pulmonary edema
•Increased temperature
•Stress or response to pain
Sinus Arrest
Causes
Myocarditis
MI
Digitalis toxicity
Atrial Flutter
Rate = 250-350 b.p.m.
Precipitates CHF
Atrial Fibrillation (afib)
Causes
COPD
CHF
Ventricular Tachycardia
(V-tac)
Causes
•CAD
•Acute MI
•Digitalis toxicity
•CHF
Rate = 100-220 b.p.m.
Ventricular Fibrillation (V-fib)
Causes
Acute MI
Asystole
The 3 major types of vessels
Arteries – carry blood away from the heart
Veins – carry blood toward the heart
Capillaries – contact tissue cells (Serving cellular needs)
Capillaries
· Very narrow (10 µm diameter, the red blood cells that travel through capillaries
are 6 µm in diameter).
Capillaries are made of thin endothelial cells (one layer thick)
• The high hydrostatic pressure on the arterial
side squeezes water and nutrients out of the
capillaries.
• Water leaving the capillaries builds up the
osmotic pressure because the blood components
have become more concentrated.
• Towards the venal end, water and waste
materials are sucked into capillaries by the
osmotic pressure.
What Causes Varicose Veins?
How to treat varicose veins
Sclerotherapy
Compression Stockings
Ablation
or
Laser treatment
(Both use heat)
• Cardiovascular System
1. Transports
• Dissolved gasses
• Nutrients
• Waste products to lungs and kidneys
• Enzymes
• Hormones from endocrine organs
2. Regulates
• pH
• Electrolyte concentration of body fluids
• Body temperature
3. Restricts fluid loss
4. Defends pathogens and toxins
1. Formed elements
• Erythrocytes
• Leukocytes
• Platelets
2. Plasma
• Blood leaves the heart via arteries that branch repeatedly
until they become capillaries
• Oxygen (O2) and nutrients diffuse across capillary walls and
enter tissues
• Carbon dioxide (CO2) and wastes move from tissues into the
blood
• Oxygen-deficient blood leaves the capillaries and flows in veins
to the heart
• This blood flows to the lungs where it releases CO2 and picks
up O2
•
The oxygen-rich blood returns to the heart
•
Sticky, opaque fluid with a metallic taste
• Color varies from scarlet (oxygen-rich) to dark red (oxygen-poor)
• pH of blood is 7.35–7.45
• Temperature is 38C, slightly higher than “normal” body
temperature
• Blood accounts for approximately 8% of body weight
• Average volume of blood is 5–6 L for males, and 4–5 L for
females
•
Plasma accounts for 55 % of the volume of whole blood.
•
92% of plasma is water, the rest consists of electrolytes and dissolved
organic compounds.
Blood plasma contains over 100 solutes, including:
•
Proteins – albumin, globulins, clotting proteins, etc…
•
Non-protein nitrogenous substances – lactic acid, urea, creatinine
•
Organic nutrients – glucose, carbohydrates, amino acids
•
Electrolytes – sodium (Na+), potassium (K+), calcium (Ca++),
chloride (Cl-), bicarbonate (HCO3-)
•
Respiratory gases – oxygen and carbon dioxide
• Biconcave discs
• RBCs have no nuclei or organelles (anucleate)
allow for a huge surface area to volume ratio
• Hematocrit – % of RBCs out of the total blood volume.
(Ave) 46 adult men & 42 adult women.
• There are roughly 5 million RBCs in each microliter of
blood
• Erythrocytes are unable to perform normal maintenance
operations and usually degenerate after about 120 days in
the circulation.
Blood
Type
A
B
AB
O
Rh Type
Percent
+
34 %
-
6%
+
9%
-
2%
+
3%
-
1%
+
38 %
-
7%
Erythroblastosis Fetalis
•
Normal response to bacterial or viral invasion
•
Move through tissue spaces
•
Granular leukocytes include neutrophils, eosinophils , and basophils.
•
Neutrophils are abundant, highly mobile phagocytes.
•
Eosinophils are attracted to foreign compounds coated with antibodies.
•
Basophils migrate into damaged tissues and release histamine, aiding in the
inflammation response.
•
Monocytes migrating into peripheral tissues become free macrophages.
•
Lymphocytes, cells of the lymphatic system, include T cells and B cells. T
cells migrate to peripheral tissues and attack foreign or abnormal cells; B
cells produce antibodies.
The coagulation process requires
calcium ions, and Vitamin K must be
available for the synthesis of five of
the clotting factors.