Cardiovascular System (Heart, vessels, blood) Flashcards
Location of the Heart:
Heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum and sits in its own space called the pericardial cavity
What act as a receiving chamber and contracts to push blood into lower chamber?
Atrias
What serve as the primary pumping chamber of the heart by propelling blood into the lungs or the rest of the body?
Ventricles
What is Fibrous pericardium made of and whats its purpose:
Made of tough, dense irregular connective tissue that protects the heart and maintains its position in the thorax
Serous pericardium:
Consists of two layers:
1. The parietal pericardium, which is fused to the fibrous pericardium
2. The inner visceral pericardium, or epicardium, which is fused to the heart and is part of the heart wall
Where is the pericardial cavity and what is it filled with:
Filled with lubricating serous fluid, lies between the epicardium and the parietal pericardium
Pericardial membrane:
Surrounds the heart consists of three layers and the pericardial cavity
What do the the pericardial membrane and the heart wall share?
The epicardium or visceral pericardium
What transports blood to and from the lungs ?
pulmonary circuit
What transports oxygenated blood to the tissues of the body and returns relatively deoxygenated blood to the heart?
Systemic circuit
Describe the path of blood from the body through the heart
Superior/Inferior Vena Cava -> Right Atrium -> Right Ventricle -> Pulmonary trunk -> Pulmonary arteries -> Lungs -> Pulmonary Veins -> Left Atrium -> Left Ventricle ->Aorta
What can initially be viewed as gasses?
Pulmonary and Systemic circuits can initially be viewed as gasses
Where does gas exchange occur?
Pulmonary capillaries: where gas exchange occurs: Carbon dioxide exits the blood and oxygen enters pulmonary trunk arteries
What artery carries deoxygenated blood?
Pulmonary arteries
What is the only arteries in the body that carry relatively deoxygenated blood?
Pulmonary trunk arteries
Atrioventricular valves:
Valves located between the atria and ventricles
Semilunar valves:
Valves at the openings that lead to the pulmonary trunk and aorta
How many layers does the heart wall have?
3 layers of unequal thickness
What are the 3 layers of the heart?
- Endocardium (inner)
- Myocardium (middle)
- Epicardium (outer)
Endocardium: Innermost layer
- Joined to the myocardium with a thin layer of connective tissue
- Endocardium lines the chambers where the blood circulates and covers the heart valves
- Simple squamous epithelium called endothelium, which is continuous with the endothelial lining of the blood vessels
Myocardium: Middle layer
- Made of collagenous fibers, plus the blood vessels that supply the myocardium and the nerve fibers that help regulate the heart
- Contraction of the myocardium pumps blood through the heart and into the major arteries
Epicardium: Outer layer:
It is composed of mesothelial cells, fat, and connective tissue
How does blood flow in the heart according to the pressure gradient?
Move from higher in pressure to lower in pressure
Diastole:
Relaxation of the heart
Atrial systole:
Contraction of atria
Ventricular systole:
Pressure rises in the ventricles, pumping blood into the pulmonary trunk from the right ventricle and into the aorta from the left ventricle
Action potential:
Triggers the muscles in the atria to contract (atrial systole)
Systemic arteries:
Provide blood rich in oxygen to the body’s tissues
Pulmonary circuit arteries:
Carry blood low in oxygen exclusively to the lungs for gas exchange.
Systemic veins:
Return deoxygenated blood to the heart.
Pulmonary veins:
Return freshly oxygenated blood from the lungs to the heart to be pumped back out into systemic circulation
Artery structure:
Muscular tube lined by smooth tissue
Vein structure:
Three layers: The intima, the inner layer lined by a smooth tissue called endothelium
Although all the layers are present, there is less smooth muscle and connective tissue.
what is a lumen?
A hollow passageway through which blood flows
Direction of blood flow in the arteries:
Conducts blood away from the heart
Direction of blood flow in the veins:
Conducts blood toward the heart
Arteries general appearance:
Rounded
Vein general appearance:
Irregular, often collapsed
What is level of pressure in the arteries:
High
What is level of pressure in the Veins:
Low
What does a vein have that an artery does not?
Valves
What is the purpose of Valves:
Assist the unidirectional flow of blood toward the heart
Vasa Vasorum:
Network of small blood vessels that supply the walls of large blood vessels, such as elastic arteries and large veins
Tunica Intima (tunica interna):
Inner most layer
Epithelial and connective tissue layer
simple squamous epithelium called the endothelium
Next to the endothelium is the basement membrane, that effectively binds the endothelium to the connective tissue
Basement membrane: provides strength while maintaining flexibility, and it is permeable, allowing materials to pass through it
Tunica Media:
Middle layer of the vessel wall
generally the thickest layer in arteries
Much thicker in arteries than it is in veins
consists of layers of smooth muscle supported by connective tissue that is primarily made up of elastic fibers, most of which are arranged in circular sheets
Tunica Externa (tunica adventitia):
Outer layer of blood vessel wall
Sheath of connective tissue composed primarily of collagenous fibers
Some bands of elastic fibers are found here as well
Veins also contains groups of smooth muscle fibers
Normally the thickest tunic in veins and may be thicker than the tunica media in some larger arteries
What are Continuous Capillaries (most common type) characterized by?
Complete endothelial lining with tight junctions between endothelial cells
Tight junction: Usually impermeable and only allows for the passage of water and ions
Metabolic products, such as glucose, water, and small hydrophobic molecules like gases and hormones, as well as various leukocytes
Where are Continuous Capillaries found?
Found in almost all vascularized tissues
What are Fenestrated Capillaries characterized by?
Contains pores (or fenestrations) in addition to tight junctions in the endothelial lining
Permeable to larger molecules
Where are Fenestrated capillaries found?
Small intestine: primary site of nutrient absorption
kidneys: which filter the blood
What are Sinusoid Capillaries (least common type) characterized by?
Flattened, and they have extensive intercellular gaps and incomplete basement membranes, intercellular clefts and fenestrations
Very large openings allow for the passage of the largest molecules, including plasma proteins and even cells
Blood flow through sinusoids is very slow, allowing more time for exchange of gases, nutrients, and wastes
Where are Sinusoid Capillaries found?
Found in the liver and spleen, bone marrow, lymph nodes , and many endocrine glands including the pituitary and adrenal glands
Components of Blood:
Plasma and formed elements
Components of Plasma:
90% water and 10% dissolved proteins, amino acids, gases, electrolytes, sugars, hormones, lipids, and vitamins
what are the most significant elements of plasma?
albumin, immunoglobulins (antibodies), and fibrinogen
Components of Serum:
Serum is plasma without its clotting factors
Serum is formed when blood is collected in a glass or plastic tube and is induced to clot
The conversion of fibrinogen to fibrin forms strands that trap all of the cellular elements
Components of Formed Elements:
Formed elements comprise 45% of blood volume
99% are RBCs, with white blood cells (WBCs) and platelets making up the rest
Function of the red blood cells?
RBCs carry hemoglobin, the iron-containing oxygen transport protein that gives blood its red color
How long does a single RBC remains in the peripheral circulation before being removed by the liver, bone marrow, or spleen?
120 days
Function of the White blood cells?
Protect the body against infection
What are the 5 types of WBCs:
- Neutrophils
- Eosinophils
- Basophils
- Monocytes
- Lymphocytes
What are the different types of lymphocytes:
T cells: Roles include directly killing infected host cells
B cells: antibody producing cells to fight bacteria and viruses
Natural killer cells: Innate immune system that control several types of tumors and microbial infections
Function of Neutrophils
Most common first responders to microbial infections (Bacterial or fungal)
Function of Eosinophils
Parasitic infections and allergic reactions (Inflammatory)
Function of Basophils
Allergic and antigen response (releases histamine causing vasodilation)
Function of Lymphocytes
Include B cells, CD4+ helper T cells,
Operate primarily in lymphatic system
Function of Monocytes
Phagocytosis of pathogens (Phagocytosis: cellular process for ingesting and eliminating particles)
presentation of antigens to Tcells
They become tissue macrophages, which remove dead cell debris and attack microorganisms
Where are platelets created?
Platelets are created in the bone marrow from megakaryocytes
How long do platelets remain in circulation?
Remains in circulation for 9 to 12 days
Hemostasis:
Refers to the processes by which blood vessels are repaired after injury
What are the 4 stages of Hemostasis:
- Vascular Phase
- Platelet Phase
- Coagulation Phase
- Fibrinolysis
AMI:
Acute Myocardial Infarction
BP:
Blood pressure
CAD:
Coronary artery disease
CCU:
Coronary care unit
CHF:
Congestive heart failure
CPR:
Cardiopulmonary resuscitation
ECG:
Electrocardiography
ECHO:
Echocardiography
HDL:
High density lipoprotein
HTN:
Hypertension
LDL:
Low-density lipoprotein
What are the tiny blood vessels that lie near cells and through whose walls gases, food, and wastes can pass?
Tissue capillaries
What are the tiny blood vessels surrounding lung tissue through which gases pass into and out of the blood?
Lung capillaries
