8 Circulatory System Flashcards
What are the functions of the cardiovascular system?
- transportation
- nutrients & wastes
- hormones
- immunity & protection
- clotting
- disease/infection
- regulation
- pH
- body temperature
- fluid levels (~5 litres of blood in body at any given time)
What are the structures of the cardiovascular system?
- Heart
- Blood vessels
- Blood
Where the boundaries of the mediastinum and what does it contain?
- A mass of organs and tissues that separates the lungs
- Boundaries:
- Superiorly: first rib
- Inferiorly: diaphragm
- Anteriorly: sternum
- Posteriorly: vertebral column
- Contains:
- Heart and its large vessels
- Trachea
- Esophagus
- Thymus & lymph nodes
- Connective tissue
What’s a general description of the pericardium?
- CT membrane that surrounds and protects the heart
- consists of 2 parts:
- fibrous pericardium
- serous pericardium
What’s the fibrous pericardium, what does it attach to and what’s its function?
- most superficial part of pericardium
- tough, inelastic, dense irregular CT
- attaches to the diaphragm inferiorly
- attaches to the CT of the blood vessels superiorly
- it holds the heart in the mediastinum and allows for movement
Describe the serous pericardium.
- thinner and deep to the fibrous pericardium
- forms a double layer around the heart
- outer layer: parietal layer of the serous pericardium
- fused to the fibrous pericardium
- inner layer: visceral layer of hte serous pericardium
- aka epicardium
- attached to the heart muscle
What’s the pericardial cavity?
- the space between the parietal and visceral layers of the serous pericardium
- filled with pericardial fluid (a thin layer of fluid to reduce friction)
What are the three layers of the heart wall?
- epicardium
- myocardium
- endocardium
What’s the aka for epicardium and what’s it made of?
- aka visceral layer of the serous pericardium
- simple squamous epithelium and CT
- gives the outer surface a smooth, slippery texture
What’s myocardium?
- cardiac muscle tissue
- site of contraction
What’s endocardium?
- endothelium overlying a thin layer of CT
- provides a smooth lining for the chambers and valves of the heart
What’s endothelium?
the layer of simple squamous epithelium that lines the cavities of the heart, blood vessels and lymphatic vessels
Which veins does the right atrium receive blood from?
- superior vena cava
- inferior vena cava
- coronary sinus
The cusps of the A-V valves are connected to tendon-like cords called ___ ___
cordae tendineae
Cordae tendineae are anchored to the ventricular wall by ___ ___
papillary muscles
Blood is ejected by the right ventricle through the ___ ___ valve into the pulmonary trunk
pulmonary semilunar
The ___ ___ divides into the right and left pulmonary arteries
pulmonary trunk
How many pulmonary veins are there and where do they feed into?
4; left atrium
What are the AKAs for the left atrioventricular (AV) valve?
aka bicuspid valve, mitral valve
What’s the aka for the right atrioventricular (AV) valve?
aka tricuspid valve
Blood is ejected by the left entricle through the ___ ___ valve into the aorta
aortic semilunar
Some of the blood in the aorta flows into ___ ___ which supply the heart with oxygen-rich blood
coronary arteries
Coronary arteries branch off from the ___ and encircle the heart
aorta
When in the cardiac cycle does the heart get its blood supply?
between beats
Specialized cardiac muscle cells generate their own APs – they are called ___ ___ because they are self-excitable
autorhythmic fibres
Autorhythmic fibres form structures that do what for the heart?
- set the rhythm of the APs that cause contraction
- form a conduction system through the heart
What’s the sequence through which the APs propogate through the heart?
- SA node
- atria
- AV node
- bundle of His
- bundle branches
- Purkinje fibres
- ventricles
What’s the aka for the bundle of His?
aka atrioventricular bundle
Once entering the bundle of His, the APs conduct along the right and left bundle branches which extend along the ___ septum to the ___ of the heart
interventricular; apex
The ___ fibres quickly conduct APs upward through the ventricles causing ventricular contraction and ejection of blood into the arteries
Purkinje
Define cardiac output
the amount of blood the heart ejects each minute
Define:
- heart rate (HR)
- stroke volume (SV)
- cardiac output (CO)
- what’s average CO?
- heart rate (HR): the number of times the heart beats in 1 minute
- stroke volume (SV): the amount of blood ejected from each ventricle with each beat
- cardiac output (CO): heart rate x stroke volume
- average CO: ~5L/min
Define preload (concerning the heart muscle)
the degree of stretch on the heart before it contracts
Ejection of blood from the heart begins when ___ ___ > ___ ___
ventricular pressure; vessel pressure (pulmonary trunk or aorta)
(when the pressure is greater in the ventricles than in the vessels, the semilunar valves open)
Define afterload (where the heart muscle is concerned)
the pressure that must be overcome before a semilunar valve can open
What are AKAs for arterioles and capillaries?
resistance vessels; exchange vessels
BVs (except capillaries) have the same 3-layered arrangement surrounding the lumen. These are:
- tunica intima
- tunica media
- tunica externa
What’s Tunica Intima made of?
simple squamous epithelium (called endothelium) and a CT basement membrane
What’s Tunica Media made of?
contains elastic fibres and smooth muscle
What’s Tunica Externa made of, what does it do/support, and what’s its aka?
- contains elastic and collagen fibres
- supports BVs an d anchors them to surrounding structures
- aka tunica adventitia
What % of fluid and what % of cells in the blood?
55% fluid; 45% cells
What are the three general functions of blood?
- transportation (nutrients, wastes, heat, hormones)
- regulation (pH, body temperature, fluid levels)
- protection (vs blood loss, foreign invaders)
Describe blood plasma
- the fluid matrix of blood
- contains dissolved substances (including nutrients, wastes, hormones)
What are the blood plasma proteins and what’s their purpose?
- albumin: transport protein
- globulins: some are transport proteins, some are involved in the immune response
- fibrinogen: essential in blood clotting
What are the general types of blood cells and what are their AKAs?
- red blood cells (RBCs) (aka erythrocytes)
- white blood cells (WBCs) (aka leukocytes)
- platelets (aka thrombocytes)
How long do erythrocytes live?
~120 days
What’s hemopoiesis (or hematopoiesis)?
the formation of RBCs
What’s the hematocrit?
% of blood volume occupied by RBCs
What’s the term denoting lower than normal hematocrit? The term denoting higher than normal?
- Lower than normal: anemia
- Higher than normal: polycythemia
These oxygen carrying proteins, contained within erythrocytes, give blood its red colour
hemoglobin
What are the main functions of leukocytes?
- fight off foreign invaders
- phagocytosis
- immune responses
What are the types of leukocytes?
- granular
- neutrophils (aka polymorphonuclears)
- eosinophils
- basophils
- agranular
- lymphocytes
- B lyphocytes
- T lymphocytes
- natural killer cells
- monocytes
- lymphocytes
What are the general functions of each type of granular leukocyte?
- neutrophils (aka polymorphonuclears): most common, function in phagocytosis (esp. bacteria)
- eosinophils: function in allergic reactions, parasitic infections
- basophils: function in stress and allergic responses
What’s the term denoting increased WBC count? Decreased WBC count?
leukocytosis; leukopenia
What are the general functions of the lymphatic system?
- drainage of excess interstitial fluid
- transportation of lipids (from the digestive system)
- protection/immune responses
What are the general structures of the lymphatic system?
- lymph (the fluid of the system)
- lymphatic vessels (to transport the fluid)
- structure and organs that contain lymph tissue
- red bone marrow (where various blood cells develop)
What are the vessels of lymphatic flow?
- capillaries
- lymphatic vessels
- trunks
- ducts
What are lymph nodes, and what’s their function?
- clusters of lymphocytes (B cells and T cells) surrounded by a dense CT capsule
- bean shaped
- ~600 nodes located along the lymphatic vessels of the body (often in groups, superficial and deep)
- function: lymph filtration (lymph flows in, foreign substances are trapped and destroyed)
What does the thoracic duct drain? The right lymphatic duct?
Thoracic duct drains:
- left side of head and neck
- left side of chest
- entire body below the ribs
- it drains into the left subclavian vein
Right lymphatic duct drains:
- right side of the head andneck
- right side of the chest
- it drains into the right subclavian vein
What maintains lymphatic flow?
- skeletal muscle pump
- diaphragmatic breathing/respiratory pump
- smooth muscle contraction (in the vessel walls - minimal contribution)
This produces B cells and immature T cells (aka pre-T cells)
red marrow
Describe the location and function of the Thymus
- located in the mediastinum
- produces mature T cells from pre-T cells
- Has “mugshot book” of all pathogens the body has ever encountered. Trains T cdells. T cells must be “fully trained” or they’ll be killed.
- large at birth, significantly atrophied by maturity
Describe the general structure, location and function of the spleen
- large mass of lymphatic tissue between the stomach and the diaphragm
- filters blood (similar to the processs in a lymph node)
- removes ruptured, worn out, defective RBCs
- stores platelets and monocytes
What’s the immune system’s first line of defence?
- skin: tightly packed keratinized cells, shedding
- mucous membranes: mucous traps microbes, cilia sweeps them out
- body fluiids
- sweat flushes the skin
- tears wash the eye
- saliva washes the teeth and mucous membranes
- urine: regular flow reduces microbial growth
- gastric juice: stomach acid destroys many bacteria
- defecation removes microbes
- vomiting removes microbes
What’s the immune system’s second line of defense?
- antimicrobial proteins: discourage microbial growth
- natural killer (NK) cells: recognize and kill microbes
- phagocytes (fixed and wandering): eat microbes
- fixed: histiocytes (CT), Kupffer cells (liver), alveolar macrophages (lungs), microglia (CNS)
- inflammation: a non-specific response to tissue damage designed to remove microbes etc., prevent their spread, and prepare the site for repair
- fever: intensifies antiumicrobial protein activity, inhibits microbial growth, speeds up repair
What’s an antigen?
a substance that is recognized as foreign and elicits an immune response
What are the 2 types of specific immune defences/responses?
- cell-mediated
- antibody-mediated
In cell-mediated immune responses, what happens when an invader is recognized?
T-cells
- activate
- enlarge
- proliferate
- differentiate (into:)
- helper T cells (trigger proliferation, perform other immune functions)
- cytotoxic T cells: migrate to the site and destroy the invader
- memory T cells: remain after the response, they don’t attack but with future infections (same invader), they make for a faster and stronger response
In antibody-mediated immune responses, what happens when an invader is recognized?
B-cells:
- activate
- enlarge
- differentiate (into:)
- plasma cells which secrete antibodies
- memory B cells: remain after the response, they don’t attack but with future infections (same invader), they make for a faster and stronger response
What sorts of things are cell-mediated immune responses effective against?
effective against fungi, parasites, viruses, some cancer cells, foreign tissue
What sorts of things are cell-mediated immune responses effective against?
effective against antigens in body fluids, extracellular pathogens (e.g. bacteria)
What’s the aka for antibodies?
aka immunoglobulins
What are antibodies and what do they do?
- proteins produced by plasma cells in response to an antigen
- they neutralize, inhibit, or destroy an antigen
