Cardiovascular System (EXAM #2) Flashcards
What is the overview of Cardiovascular System?
- Heart, Blood vessels, Blood
- Transport: gases, nutrients, hormones, wastes, heat
- Protection: disease, fluid loss (clotting)
Heart
In a cavity called the mediastinum (= space between lungs within thoracic cavity)
What are the structures of the Heart?
- Coverings = Pericardium
- Heart Wall
- Four chambers of the heart and associated blood vessels
- Septa (separate chambers)
- Cardiac (Fibrous) Skeleton
- Valves (for one way flow of blood)
- Cardiac Muscle Cells
Coverings = Pericardium
- Double-walled sac surrounding heart
- 3 layers:
- Fibrous Pericardium
- Perietal Pericardium
- Visceral Pericardium
- Between pericardial layers = pericardial cavity with serous fluid (lubricates)
Fibrous Pericardium
- Outermost layer = dense irregular connective tissue
- Anchors to surrounding strucutures e.g. diaphragm, great vessels (aorta, Vena Cava, etc)
Perietal Pericardium (Serous Pericardium)
- 2 layers - epithelial & connective
- Connected to fibrous pericardium
- Pericardial Sac
Visceral Pericardium (Serous Pericardium)
- = Epicardium
- 2 layerss - epithelial & connective
- Fused to heart surface, so is part of heart wall
Heart Wall
3 Parts:
1. Epicardium
2. Myocardium
3. Endocardium
Epicardium
Simple squamous epithelium and connective tissue
Myocardium
- = cardiac muscle
- Arranged in spiral/circular pattern, reinforced with connective tissue
Endocardium
- Simple squamous epithelium and connective tissue
- Epithelium named endothelium - lines inner surface of heart and ALL blood vessels
Four chambers of the heart and associated blood vessels
- Right Atrium
- Left Atrium
- Right Ventricle
- Left Ventricle
Right Atrium
- Three major veins connected to the right atrium that carry deoxygenated blood into the chamber:
- Inferior vena cava (carries blood from body below heart)
- Superior vena cava (carries blood from body above heart)
- Coronary Sinus (carries blood from the myocardium)
Left Atrium
- 4 veins carry oxygenated blood into the left atrium from the lungs:
- Left pulmonary veins
- Right pulmonary veins
Right Ventricle
1 artery, the pulmonary trunk exits the right ventricle and then divides to form 2 pulmonary arteries (left and right). These carry deoxygenated blood towards the lungs
Left Ventricle
1 artery, the aorta, exits the left ventricle and carries oxygenated blood to all organ systems
Septa (separate chambers)
- Interatrial Septum
- Separates atria
- Interventricular Septum
- Separates ventricles
Cardiac (Fibrous) Skeleton
- Fibrous connective tissue separating atria & ventricles
- Provides firm attachment point for cardiac muscles
- Forms solid rings around heart valves, base of aorta and pulmonary trunk that provide structural support for these structures and hold them in place
- Provides electrical insulation - prevents simultaneous contraction of atria and ventricles
Valves (for one way flow of blood)
- Atrioventricular (AV) valves
- Semilunar valves
Atrioventricular (AV) valves
- Bicuspid (mitral) valve
- Tricuspid valve
- Chordae Tendineae
Bicuspid (mitral) valve
- Between left atrium and left ventricle
- Has 2 sheet-like cusps composed of connective tissue
Tricuspid valve
- Between right atrium and right ventricle
- Has 3 sheet-like cusps composed of connective tissue
Chordae Tendineae
- Strings of connective tissue that attach atrioventricular valve cusps to papillary muscles that project from the ventricular myocardium
- Prevent eversion of cusps
Semilunar valves
- 3 cup-like cusps each
- Aortic
- Separates left ventricle & aorta
- Pulmonary
- Separates right ventricle & pulmonary trunk
- Aortic
Cardiac Muscle Cells
- Includes two cell types:
- Contractile cells
- Conduction System cells
Contractile cells
- Forms majority of myocardium
- Similarities to Skeletal muscle:
- Striated (myofibrils with sarcomeres)
- Has sarcoplasmic reticulum & T-tubules
- Differences:
- Branched (myofibrils with sarcomeres)
- Uninucleated discs = region where two fibers meet
- Contain anchoring and gap junctions
Conduction System cells
- Forms remainder of the myocardium
- Cardiac muscle cells that are modified to produce and conduct electrical impulses - DO NOT CONTRACT
- Have many gap junctions that help electrical signals to spread very quickly
What are the parts of Conduction System cells?
- Sinoatrial (SA) node
- Atrioventricular (AV) node
- Atrioventricular Bundle (Bundle of His)
- Atrioventricular (AV) Bundle Branches
- Purkinje fibers
Sinoatrial (SA) node
- In right atrium at base of superior vena cava
- Generates impulses the fastest - sets pace
Atrioventricular (AV) node
Base of right atrium
Atrioventricular Bundle (Bundle of His)
- Superior part of interventricular septum
- Electrically connects atria to ventricles
Atrioventricular (AV) Bundle Branches
Carry impulse to apex (bottom tip) of the heart
Purkinje fibers
- Terminal fibers in ventricles (not found in atria) that carry signals from apex upward to all parts of the ventricle
- NOTE: Electrical signal spreads from conduction system to contractile cardiac cells then they contract
What are the general structures of blood vessels?
- Tunica externa - CT
- Tunica Media
- Tunica intima/interna
- Lumen
Tunica Media
- Smooth muscle
- Elastic Fibers (CT)
Tunica intima/interna
- Endothelium - simple squamous epithelium
- Continous with endocardium
Lumen
Contains blood (not a layer!)
What are the blood vessels types?
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
Arteries
- Carry blood AWAY from heart (does NOT refer to oxygenated or deoxygenated blood)
- 2 types:
- Elastic Arteries
- Muscular Arteries
Elastic Arteries
- Large conducting arteries exiting the heart
- Elastic CT in all 3 layers
- Largest Arteries (near heart)
- e.g. Aorta
Muscular Arteries
- Smaller Distributing arteries
- A LOT of smooth muscle
- Most arteries
- e.g. Coronary Artery
Arterioles
- Little Arteries
- Regulate blood flow + blood pressure
Capillaries
- ONLY tunica intima - endothelium (one cell layer) + basement
- Allow exchange of gases + nutrients
- Most have gasps between cells that allow exchange of fluid + solutes with the interstitial fluid
Venules
- Collect blood from capillaries
- Intima (endothelium) with thin media/externa layers
Veins
- Carry blood INTO heart (vein) (does not refer to oxygenated or deoxygenated blood)
- Large lumen
- Can have one-way valves that prevent backflow of blood
- Thin media - more connective tissues but less smooth muscle than arteries
The Blood Flow
- Heart
↓ - Elastic Arteries
↓ - Muscular Arteries
↓ - Arterioles
↓ - Capillaries
↓ - Venules
↓ - Veins
↓ - Heart
What is Circulatory Routes?
- Closed, double circulation
- Closed
- Blood confined to heart + blood vessels
- Double
- 2 routes (pulmonary + systemic)
What are the 2 Circulatory Routes?
- Adult Circulation
- Fetal Circulation
What are the 3 types of circulation in a Adult Circulation?
- Pulmonary Circulation
- Systemic Circulation
- Coronary Circulation
Pulmonary Circulation
- For oxygenation of the blood
- Carries blood from right ventricle to lungs via pulmonary arteries (deoxygenated blood)
- Picks up oxygen in lungs via capillaries
- Carries blood from lungs to left atria via pulmonary veins (oxygenated blood)
Pulmonary Circulation Cycle
- Right Ventricle
↓ (deoxy) - Pulmonary Arteries
↓ (deoxy) - Capillaries in respiratory portion of lungs
↓ (oxy) - Pulmonary Veins
↓ (oxy) - Left Atrium
Systemic Circulation
- For delivery of oxygenated blood to all other tissues
- Carries blood from left ventricle to organs via aorta (oxygenated)
- Organs take up oxygen from blood via capillaries
- Carries blood from organs to right atrium via superior and inferior vena cava (deoxygenated)
- Overall Route: Left ventricle to right atrium = systemic circulation
What are the subdivisions of Systemic Circulation?
- Include routes to individual organs/organ systems, for example:
- Cerebral = brain
- Hepatic = liver
- Coronary = heart
- Bronchial = parts of respiratory system
- and many more
Coronary Circulation
- Oxygenated Blood
- Left ventricle → Aorta
- Aorta → (right & left) Coronary Arteries
- Right Coronary Artery → Posterior Interventricular Artery & Marginal Artery
- Posterior Interventricular Artery & Marginal Artery → Arterioles
- Left Coronary Artery → Anterior Interventricular Artery & Circumflex Artery
- Anterior Interventricular Artery & Circumflex Artery → Arterioles
- Arterioles → Capillaries in myocardium
Coronary Circulation (PART 2)
- Deoxygenated Blood
- Capillaries in myocardium
↓
- Venules
↓
- Cardiac veins
↓
- Coronary Sinus ( a blood vessel)
↓
- Right atrium
Fetal Circulation
- Fetus gets oxygen (O2), nutrients from + expels wastes to mother’s blood
- Exchange site in the placenta
- Blood supplies in close together, but do not mix
- Following birth all shunts normally become closed
What are the differences between Fetal Circulation and Adult Circulation?
- Umbilical Vein
- Lungs + Liver are late to develop and their functions handled by the maternal organs
- Umbilical Arteries
Umbilical Vein
- Towards the fetal heart
- Carries oxygenated blood from placenta to vena cava
Lungs + Liver are late to develop and their functions handled by the maternal organs
- 3 shunts allow most blood to bypass these organs (minimal blood flow to these organs for nourishment/growth):
- Ductus Venosus
- Foramen Ovale
- Ductus Arteriosus
Ductus Venosus
- Connects umbilical vein (oxygenated blood) to inferior vena cava (deoxygenated blood)
- Permits most of the oxygenated blood coming from the placenta to bypass the liver capillaries
- Oxygenated and deoxygenated blood mixes in inferior vena cava and enters fetal right atrium
Foramen Ovale
- Hole in interatrial septum
- Allows blood to move from the Right to Left atrium
- Bypasses the uninflated fetal lung (fetus is not breathing, so no gas exchange takes place here)
Ductus Arteriosus
- Connects pulmonary trunk and aorta
- Bypasses the uninflated fetal lung (fetus is not breathing, so no gas exchange takes place here)
Umbilical Arteries
- Away from fetal heart
- Returns mixed blood to placenta
Characteristics of Blood
- Higher viscosity than H2O
- pH 7.35 - 7.45
- 4 - 6 L in an adult
Composition Overview of Blood
- Plasma (matrix) makes up ~55-60% of blood volume
- Fluid Portion with solutes
- Formed elements makes up ~40-45% of blood volume
- Cellular portion
Composition Details of Blood
- Plasma (matrix
- Formed Elements
What is plasma?
- Matrix
- = Blood minus formed elements
What is Plasma composed of ?
- H2O - 90%
- Proteins - 8%
- Other solutes - 2%
Proteins - 8% (PART 1)
- Albumins
- Most plentiful plasma protein
- Carries substances such as hormones, enzymes and medicines throughout the body
- Helps control tissue water balance
Proteins - 8% (PART 2)
- Fibrinogen
- Clot formation
- Globulin
- Antibodies (immunity) - detect and bind foreign invaders (bacteria, viruses, …)
Other solutes - 2%
- Nutrients
- Vitamins
- Wastes
- Electrolytes
- Blood Gases - Oxygen (O2) and Carbon Dioxide (CO2)
What are Formed Elements?
- Red Blood Cells
- WBC - Leukocytes
Red Blood Cells (PART 1)
- Erythrocytes = most abundant cell type in the body
- Binds to and transports most of the oxygen in the blood
- Hematocrit
- Is the percetage (%) of blood volume that is made up of red blood cells (usually around ~45%)
Red Blood Cells (PART 2)
- Have a biconcave disc shape
- Are anucleate (lack a nucleus and all other organelles) when mature
- Life span ~120 days
- Old cells destroyed in the liver & spleen
What does Red Blood Cells Contain?
Hemoglobin
- Iron-containing pigment protein
- Four globin chains (protein)
- Four iron (Fe) containing heme groups (gives blood its red colour)
- 1 iron per heme
- Site of reversible oxygen (O2) binding
WBC - Leukocytes
- Nucleated
- Life span varies - days to years
- Defend against disease
- 2 types:
- Granulocytes
- Agranulocytes
Granulocytes
- Contain visible protein granules
- 3 parts
- Neutrophils (~60%)
- Eosinophils (~3%)
- Basophils (~1%)
Neutrophils (~60%)
- All phagocytic (engulf + digest incaders)
- Kill bacteria
Eosinophils (~3%)
Predominantly attack blood parasites
Basophils (~1%)
Release chemicals involved in inflammation and reduction of blood clotting during immune responses
Agranulocytes
- Lack visible protein granules
- 2 types:
- Lymphocytes (~35%)
- Monocytes (~5%)
Lymphocytes
For immunity (resistance to disease)
What are the 2 types of Lymphocytes?
- T Lymphocytes
- B Lymphocytes
T Lymphocytes
- Activate immune response
- Kill tumor or virus infected/diseased cells directly
B Lymphocytes
Become plasma cells that release antibodies that circulate in the plasma
Monocytes (~5%)
Enter tissue and enlarge to become macrophages (meaning “big eaters”) phagocytic
Platelets
- Fragments of cells called megakaryocytes
- Involved in clotting
- Life span = ~ 10 days if not used for clotting
Hemopoiesis/Hematopoiesis
- = formation of blood cells
- All blood cells arise indirectly from hemocytoblast cells (which are a type of stem cells) in red bone marrow
- Red marrow in an adult is located in:
- Axial skeleton
- Pelvic + Pectoral girdles
- Proximal ends of humerus + femur
- Red marrow in an adult is located in:
What are the related Medical Conditions?
- Atrial septal defect
- Atherosclerosis
Atrial septal defect
- A hole in the interatrial septum
- Most common type occurs due to incomplete closure of the foramen ovale
Atherosclerosis
Build up of fat deposits in the tunica intima that leads to narrowing or blockage of arteries