Unit 12 - Cardiovascular System Flashcards
What does the cardiovascular system consist of
- heart
- blood vessels
- blood
Function of the cardiovascular system
- Transport: gases, nutrients, hormones, wastes, heat
- Protection: disease, fluid loss (clotting)
Where is the heart
In a cavity called the mediastinum
Mediastinum
Space between lungs within thoracic cavity
Heart coverings
- called the pericardium
Pericardium
- Double walled sac surrounding the heart
- 3 layers
Fibrous pericardium
- outermost layer (dense irregular CT)
- anchors to surrounding structures
- ex. Diaphragm, great vessels (aorta, vena cava)
What is the Serous pericardium composed of
- Parietal pericardium
- Visceral pericardium
Parietal pericardium
- 2 layers (epithelial and connective)
- connected to fibrous pericardium
- pericardial sac
Visceral pericardium
- epicardium
- 2 layers (epithelial and connective)
- heart wall
- fused to heart surface, makes it part of heart wall
Pericardial cavity
- between pericardial layers
- with serous fluid (lubricates)
3 parts of heart wall
- Epicardium
- Myocardium
- Endocardium
What is the epicardium
Visceral pericardium
What kind of tissue is the epicardium made of
Simple squamous epithelial and connective tissue
Myocardium
- cardiac muscle
- arranged in spiral/circular pattern
- reinforced with CT
Endocardium tissue type
- simple squamous epithelium
- epithelium named endothelium (lines inner surface of heart and all blood vessels)
Right atrium blood vessels
Has 3 major veins that carry deoxygenated blood into the chamber
1. Inferior vena cava (carries blood from body below heart)
2. Superior vena cava (carries blood from body above heart)
3. Coronary sinus (carries blood from the myocardium)
Left atrium blood vessels
4 veins that carry oxygenated blood into the left atrium from the lungs
1. Left pulmonary veins (inferior and superior)
2. Right pulmonary veins (inferior and superior)
Right ventricle blood vessel
- 1 artery
- aorta
- exits the left ventricle and carries oxygenated blood to all organ systems
Septa
Separate chambers
Interatrial septum
Separates atria
Interventricular septum
Separates ventricles
What is the cardiac (fibrous) skeleton
Fibrous CT separating atria and ventricles
What does the cardiac (fibrous) skeleton provide
- Firm attachment point for cardiac muscles
- electrical insulation (prevents stimultaneous contraction of atria and ventricles)
What does the cardiac (fibrous) skeleton form
- solid rings around heart valves, base of aorta and pulmonary trunk
- rings provide structural support for these structures and hold them in place
What happens when heart is beating
- there are electrical impulses telling the heart to beat
- don’t want all sections to be beating at once
- needs insulation
Valves for one way blood flow
- Atrioventricular (AV) valves
- Semilunar valves
Types of atrioventricular valves
- Bicuspid valves
- Tricuspid valves
Bicuspid (mitral) valve
- on left side
- between left atrium and ventricle
- has 2 sheet-like cusps composed of CT
Tricuspid valve
- on right side
- between right atrium and right ventricle
- has 3 sheet-like cusps composed of CT
Chordae tendineae
- strings of CT
- attach atrioventricular valve cusps to papillary muscles that project from the ventricular myocardium
- prevent eversion cusps
Semilunar valves
- 3 cup-like cusps each
- types
1. Aortic
2. Pulmonary
Aortic semilunar valves
Separates left ventricle and aorta
Pulmonary semilunar valves
Separates right ventricle and pulmonary trunk
What are cardiac muscle cells
Cells that set the pace and tell the heart to beat
Cardiac muscle cell types
- Contractile cells
- Conduction system cells
What do contractile muscles form
Majority of myocardium
Contractile cardiac muscle cells similarities to skeletal muscle
- Striated
- Has Sarcoplasmic reticulum and T-tubules
Contractile cardiac muscle differences from skeletal muscle
- Branched
- Uninucleated
- Intercalated discs
- Contain anchoring and gap junctions
Intercalated discs
Region where 2 fibres meet
(Dark bands)
According and gap junctions of cardiac muscle cells
- for communication
- atria to ventricular contraction
What affects the amount of blood that gets pumped out of the heart
Pressure
- direct relationship (increase in pressure, increase in blood that gets pumped out)
What do electrical vents cause
Contractile vents
What do conduction system cardiac muscle cells form
Remainder of myocardium
What are conduction system cardiac muscle cells
Cardiac muscle cells that are modified to produce and conduct electrical impulses
Do conduction system cells contract
NO!!
What do conduction system cardiac muscle cells have
Many gap junctions that help electrical signals spread very quickly
parts of conduction system cardiac muscle cells
- Sinoatrial (SA) nodes
- Atrioventricular (AV) nodes
- Atrioventricular bundle (bundle of his)
- Atrioventricular (AV) bundle branches
- Purkinje fibres
What is everything connected through
Electrical signals
Modified/specialized cardiac muscle cells
- conduction system
- generate electrical signals
- conduction
“Normal” cardiac muscle cells
- myocardium
- contract
Sinoatrial (SA) node
- artificial pacemaker
- in rich atrium at base of superior vena cava
- generates impulses the fastest (sets the pace)
Atrioventricular (AV) node
- base of right atrium
Atrioventricular bundle (bundle of his)
- superior part of interventricular septum
- electrically connects atria to ventricles
What would happen is the atrioventricular bundle stopped working
Would be like shutting down highway 1 and trying to get east to west
Atrioventricular (AV) bundle branches
- carry impulses to apex of heart
Apex of heart
- bottom tip
- most inferior part of the heart
Purkinje fibres
- terminal fibres in ventricles (NOT IN ATRIA) that carry signals from apex upward to all parts of the ventricle
- electrical signal spreads from conduction system to contractile cardiac cells then they contract
General structure of blood vessels (except capillaries)
- Tunica external
- Tunica media
- Tunica intima/interna
- Lumen
Structure of capillaries
Only have one layer, all other blood vessels have 3 layers
Tunica
Covering
Tunica external
- connective tissue
- most external layer
Tunica media
- middle layer
- smooth muscle
- elastic fibres (CT)
Tunica intima/interna
- innermost layer
- in direct contact with blood
- endothelium (simple squamous epithelium)
- continuous with endocardium
Endothelium
- name of the layer not the tissue type
- covers inner surface of heart as well as blood vessels
- makes up heart wall
- not a tissue type at all
Lumen
- not the innermost layer because it’s NOT A LAYER
- contains blood
- also NOT A CAVITY
- just a space
Blood vessel types
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
Arteries
- carry blood AWAY from heart
- does not refer to oxygenated or deoxygenated blood
Elastic arteries
- large conducting arteries exiting the heart
- elastic CT in all 3 layers
- largest artery (near heart)
- ex. Aorta
Muscular arteries
- smaller distributing arteries
- a LOT of smooth muscle
- most arteries
- ex. Coronary artery
Arterioles
- little arteries
- regulate blood flow and blood pressure
What do all epithelial tissues have
Basement membranes
Capillaries
- very tiny
- ONLY tunica intima (endothelium) + basement membrane
- allow exchange of gases and nutrients
- most have gaps between cells that allow exchange of fluid + solutes with the interstitial fluid
Blood vessel analogy
Elastic and muscular arteries= highways
Arterioles= smaller roads branching off
Capillaries= driveway
Venules
- collect blood from capillaries
- intima (endothelium) with thin media/external layers
Veins
- more superficial
- carry blood INTO heart
- veIN, INto
- large lumen
- can have one way valves that prevent backflow of blood
- thin media (CT but less smooth muscle than arteries)
Close circulation routes
Blood confined to heart and blood vessels
Double circulatory routes
2 routes (pulmonary + systemic)
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 atrial vis pulmonary veins (oxygenated blood)
Pulmonary circulation flow chart
Right ventricle - pulmonary arteries - capillaries in respiratory portion of lungs - pulmonary veins - 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 of systemic circulation
Left ventricle to right atrium
Subdivision of systemic circulatory routes
- include routes to individual organs/organ systems
- examples:
1. Cerebral= brain
2. Hepatic= liver
3. Coronary= heart
4. Bronchial= parts of respiratory system
Coronary circulation
- visible externally
- starts in the heart
- ends in the heart
DRAW OUT FLOW CHART
Fetal circulation
- we rely on our mothers systems (keeps us alive in utero)
- fetus gets oxygen, nutrients from and expels wastes to mothers blood
Exchange site for fetal circulation
- in the placenta
- blood supplies get close together, but do not mix
Umbilical vein
- towards the fetal heart
- carries oxygenated blood from placenta to vena cava
Lungs and liver of fetus
- almost unfunctional
- late to develop and there functions are handled by the maternal organs
- 3 shunts allow most blood to bypass these organs
1. Ductus venosus
2. Foramen ovale
3. Ductus arteriosus
Ductus venosus
- bypasses liver
- 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
- bypasses lungs
- 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
What happens to shunts after birth
all shunts normally become closed
Umbilical arteries
- away from fetal heart
- returns mixed blood to placenta
Viscosity of blood
Higher than H20
Blood vs water
Blood is thicker than water, has more cells in it
pH of blood
7.35-7.45
- not acidic
How much blood do we have in our bodies
4-6 L in an adult
- think jug of milk
Composition of blood
- Plasma (matrix)
- approx. 55-60% of blood volume
- fluid portion with solutes - Formed elements
- approx. 40-45% of blood volume
- cellular portion
Plasma (matrix)
blood minus formed elements
What is plasma composed of
- H20
- Proteins
- Other solutes
Proteins in blood
- Albumins
- Fibrinogen
- Globulin
- Protein based hormones and enzymes
Albumins
- most plentiful plasma protein
- carries substances such as hormones, enzymes and medicines throughout the body
- helps control tissue water balance
Fibrinogen
Clot formation
Globulin
- antibodies (immunity)
- detect and bind foreign invaders (bacteria, viruses)
Other solutes of blood
- nutrients
- vitamins
- wastes
- electrolytes
- blood gases (oxygen and carbon dioxide)
Red blood cells
- erythrocytes
- most abundant cell type in the body
What do red blood cells do
Bind and transport most of the oxygen in the blood
Hematocrit
Is the percentage of blood volume that is made up of red blood cells
Red blood cell shape
Biconcave shape
How many nuclei do red blood cells have
NONE
- they are anucleate when mature
- also have a lack of all other organelles as well
Red blood cell life span
120 days
Where are old cells recycled
In the liver and spleen
What do red blood cells contain
Hemoglobin
1. Four globin chains (protein)
2. Four iron (Fe) containing heme groups
Hemo
Means blood
Hemoglobin
- iron containing pigment protein
- gives blood its red colour
- site of reversible oxygen binding (drops off O2 at lungs, picks up O2 at cells)
White blood cells
- nucleated
- life span varies (days to years)
- defend against disease
2 types of white blood cells
- Granulocytes
- Agranulocytes
Granulocytes
- contain visible protein granules
- include:
1. Neutrophils
2. Agranulocytes
Neutrophils
- All phagocytic (engulf + digest invaders)
- kill bacteria
Eosinophils
Predominantly attack blood parasites
Basophils
- release chemicals involved in inflammation and reduction of blood clotting during immune responses
Agranulocytes
- lack visible protein granules
- include:
1. Lymphocytes
2. Monocytes
Lymphocytes
- for immunity (resistance to disease)
- only kill a couple bacteria, then die off
- predominantly found within lymphatic tissues
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
Organelles in white blood cells
They have none
Monocytes
- kill way more bacteria
- enter tissue and enlarge to become macrophages (meaning “big eaters”) phagocytic
Platelets
- fragments of cells called megakaryocytes
- involved in clotting
Life span of platelets
- less than 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
Where is red bone marrow in an adult located
- Axial skeleton
- Pelvic + pectoral girdles
- Proximal ends of humerus and femur
Atrial septal defect
- Cardiovascular related medical condition
- a hole in the interatrial septum
- most common type occurs due to incomplete closure of the foramen ovale
Atherosclerosis
- Cardiovascular related medical condition
- build up of fat deposits in the tunica intima that leads to narrowing or blockage of arteries
