Cardiovascular System Flashcards
Cardiovascular system 3 components
- Heart
- Blood vessels
- Blood
Describe cardiac muscle
Involuntary striated muscle cells with filaments arranged in sarcomeres. short branched cells separated by intercalated discs containing many gap junctions for fast spread of electrical impulses between individual cells.
What are the 4 chambers of the heart?
- Right atrium = receives low o2 high co2 blood from body
- Right ventricle = sends blood to pulmonary trunk for lungs
- Left atrium = receives high o2 low co2 blood from lungs
- Left ventricle = sends blood to aorta for body
What are the 4 heart valves?
Atrioventricular valves = tricuspid (between RA + RV) and bicuspid (between LA + LV)
Semilunar valves = Aortic (between aorta + LV) and pulmonary (between pulmonary and RV)
All stop backflow of blood by creating a seal.
Describe the heart wall
- Endocardium = smooth simple squamous cell epithelium layer to reduce resistance of blood flow.
- Myocardium = thickest layer, contains cardiac muscle to contract the chambers. Thickness varies based on pressure (atrium thin due to less pressure, ventricles thicker for contractions, LV thicker than RV as it has a longer distance of blood to pump.
- Epicardium = external layer, contains pericardium (fibrous, cavity and serous), allows movement while anchoring and containing heart.
Describe the hearts external anatomy
- size of a fist
- 2 atria (receiving chambers)
2 ventricles (pumping chambers) - sulci (grooves)
What are the 5 components of gross anatomy?
- location
- shape, size and appearance
- relations
- blood supply + drainage
- lymphatic drainage
Describe the hearts location
Thoracic cavity, mediastinum, inferior anterior portion. Lies mostly to the left of the midline.
Describe the hearts relations
anterior = sternum
posterior = esophagus
inferior = diaphragm
superior = great vessels
left lateral = left lung
right lateral = right lung
Describe the hearts lymphatic drainage
lymph capillaries drain heart into collector vessels that run along major branches of coronary arteries which empty into either the left lymphatic thoracic duct or the right lymphatic duct.
What are the 3 lymph node groups of the heart?
- anterior mediastinal
- tracheobronchial
- paratracheal
Describe the hearts blood supply and drainage
Myocardium has its own network of blood vessels. This is called the coronary circulation which has coronary arteries, veins and capillaries.
Explain the blood flow of the heart
Right side:
- right atrium receives low o2 high co2 blood from superior and inferior vena cava veins
- atrium contracts, forcing blood through tricuspid valve and into right ventricle
- ventricle contracts and forces blood through pulmonary valve and into pulmonary trunk
- blood is taken to lungs for exchange
Left Side:
- Left atrium received rich o2 low co2 blood from pulmonary veins
- atrium contracts, forcing blood though bicuspid valve and into left ventricle
- ventricle contracts and forces blood through aortic valve and into aorta
- blood is taken to rest of body for exchange
What are the 5 blood vessel types?
- arteries
- arterioles
- capillaries
- venules
- veins
Simple blood vessel structure
up to 3 layers, not all blood vessels have all 3. Tunica interna, tunica media and tunica externa.
Tunica Interna
functions to offer least resistance to blood flow.
simple squamous epithelium.
consistent across all blood vessels .
Tunica media
functions to direct where blood is needed via vasodilation (lumen enlarges, more flow) and vasoconstriction (lumen gets smaller, less flow).
smooth muscle
thickness varies based on pressure differences.
Tunica externa
functions to help anchor the vessel to surrounding tissue, accommodates blood vessels and nerves for larger vessels.
elastic and collagen fibers.
reasonably consistent across blood vessels, not present in capillaries.
Artirie Basic Function
carry blood away from the heart, built to withstand pressure, thick walls.
Large elastic arteries
closest to heart.
more elastic fibers to absorb kinetic energy and propel blood through vessel.
medium muscular artries
supply muscular organs
more smooth muscle than elastic for vasoconstriction/dilation.
Arterioles
abundant microscopic vessels taking blood to capillary beds.
no tunica externa, too small to require
Veins
Take blood to heart then lungs, built to optimize blood flow and not pressure.
large lumen, thin walls.
Vein valves
Folds in tunica interna forming cusps. prevent blood backflow.
Venules
small thin walled veins, take blood away from capillary beds.
Muscoskeletal pump
as muscles contract and relax they squeeze on nearby vessels forcing blood through them, valves prevent backflow.
Capillaries
site of exchange, substances pass through one layer of simple squamous epithelium and basement membrane. blood flows from arteriole to venule, sphincters made from smooth muscle cells contract decreasing or stopping flow depending on bodies needs.
Describe the 3 capillary types
- continuous = continuous layer of endothelial cells, contains intercellular clefts (gaps in between cells) to allow substances to move through.
- fenestrated = pores for faster exchange of solutes.
- sinusoids = wide large pores between endothelial cells with an incomplete or missing basement membrane, allows for free and rapid exchange.
Blood functions + structure
- transportation
- regulation
- protection
extracellular matrix with cellular population and a fibrous element. (connective tissue)
Blood cell formation
located in red bone marrow of spongy bone. pluripotent stem cells produce myeloid (red blood cells, platelets, monocytes, neutrophils) and lymphoid (all lymphocytes).
Describe red blood cells
erythrocytes
- biconcave discs for surface area enlargement (exchange) and flexibility
- lack organelles to conserve oxygen
- contain hemoglobin for transport of O2 and CO2
Describe White Blood Cells
- Innate and acquired immunity
- fight foreign invaders
- granular = neutrophils, eosinophils and basophils
- a-granular = lymphocytes and monocytes
Describe Phagocytes
Neutrophils = Get to damage first, phagocytose bacteria then die.
Monocytes = Arrive in larger numbers, differentiate into Macrophages.
Macrophages = Phagocytose bacteria and recycle them. Display antigenic markers on cell membrane for lymphocytes.
Describe Dendritic Cells
Derived from monocytes. Present in all tissues which have contact with the outside world. Phagocytose bacteria then present antigenic markers on cell membrane for lymphocytes.
Describe Basophils and Eosinophils
Basophils = Intensify inflammation (allergies).
Eosinophils = Effective against parasitic worms.
Describe Lymphocytes
T Cells = Kill abnormal cells.
B Cells = Produce antibodies and attach them to bacteria to mark for phagocytosis.
NK Cells = Kill all cells not displaying the correct self marker.
Describe Platelets
Megakaryocytes splinter into many fragments creating platelets. Stop blood loss by creating a platelet plug and releasing blood clotting chemicals at the site.
