Cardiovascular Flashcards
Types of blood vessels
Arteries (carry blood away from the heart)
Veins (return blood to the heart)
Capillaries (connect the smallest arteries to the smallest veins)
Blood vessel layers
Tunica externa
Tunica media
Tunica intima (endothelium)
Tunica externa
Outer layer of fibrous connective tissue that supports and protect the vessel
Tunica media
Middle layer of smooth muscle and elastic tissue
Tunica intima
Innermost layer that keeps blood from sticking to vessel walls so it can flow freely
Categories of arteries
Conducting arteries
Distributing arteries
Arterioles
Conducting arteries
Largest
Closest to heart
Elastic
Distributing arteries
Lead to specific organs
Muscular
Arterioles
Smallest
Resistance vessels
Veins
Become smaller as they lead away from the heart
Have thinner walls than artistes
Have a great ability to stretch
Can constrict extensively
Categories of veins
Venules
Medium sized veins
Large veins
Venules
Smallest
Have thin, porous walls
Medium sized veins
Formed by convergence of Venules
Contain one way valves
Large veins
Formed by convergence of Venules
Have thick tunica externa
Capillaries
Microscopic
Link Arterioles to Venules
Are exchange vessels
Have extremely thin walls
Have very small diameters
Capillary exchange
Walls allow for two way exchange
Release chemicals (such as oxygen, glucose) to tissues
Take up waste
Mechanisms of exchange include diffusion, filtration and osmosis
Capillaries release oxygen and take up carbon dioxide from surrounding tissue through the process of ?
Diffusion
What is the pathway of pulmonary circulation?
-Blood leaves the right ventricle through the pulmonary trunk into the right and left pulmonary arteries
-pulmonary arteries enter the lungs where they branch into lobar arteries and then into capillary beds
-capillaries from Venules which merge into veins
-Veins merge until they form the pulmonary vein, which returns blood to the left atrium
What is the pathway of systemic circulation
-blood leaves the left ventricle into the ascending aorta, the aortic arch and the descending aorta
-arteries branch off the aorta to supply blood to the heart, head neck and body
-arteries branch into Arterioles which join capillaries
-capillaries merge to form Venules; which marge to form veins
-veins marge into the superior and inferior vena cava which returns the blood to the right atrium
Peripheral Resistance
- Resistance to flow results from friction of blood against walls of vessels.
- Amount of friction depends on
◦ Blood viscosity
◦ Vessel diameter
- Vasoconstriction
- Adjusting the diameter of vessels is the chief way of controlling blood pressure.
- Vasodilation
- Blood Velocity
- Vessel diameter affects how fast blood flows.
What is the pathway of systemic circulation?
◦ Left ventricle to Aortic Valve to Aorta
◦ Aorta to Arteries to Arterioles to Capillaries
◦ Capillaries to Venules to Veins
◦ Veins to SVC/IVC to Right Atrium
- Components of the Lymphatic System:
Lymphatic vessles
Lymph
Lympahtic tissue
Lymphatic organs
Functions of the Lymphatic System
- Maintenance of fluid balance
- Absorption of fats
- Immunity
- How do lymphatic vessels function?
◦ Lymph fluid containing bacteria, lymphocytes, and other cells flows
into the vessels through gaps between the cells
◦ The vessels converge to form larger lymph vessels that periodically
empty into lymph nodes
◦ Eventually the lymph vessels converge into two collecting ducts:
-Right lymphatic duct
-Thoracic duct
Lymphatic Tissues
- Consist of patches of specialized tissue throughout the body
- House a variety of lymphocytes
- Lymphocytes also reside in mucosa linings
◦ Known as mucosa-associated lymphatic tissue (M A L T)
◦ Allow body to protect against invaders
Tonsils
Pharyngeal tonsil
Palatine tonsil
Lingual tonsils
-Pharyngeal tonsil (adenoids)-
sits on the wall of the pharynx, just behind the nasal cavity
-Palatine tonsil
Lies in the posterior of the oral cavity (visible ones at back of throat)
Lingual tonsils
Concentrated patches on each side of the base of the tounge
Thymus
- Produces a hormone called thymosin that stimulates lymphocyte
production - Training ground for lymphocytes
◦ Immature T lymphocytes travel from red bone marrow to learn from
other lymphoid cells - Shrinks as we age
- Roles of the lymph nodes:
◦ Remove pathogens and foreign material in the lymph
◦ Location of some lymphocyte and monocyte maturation
Major lymph node clusters:
Cervical lymph nodes in the neck
◦ Axillary lymph nodes in the armpit
◦ Inguinal lymph nodes in the groin
Spleen Functions
- Immunity
- Destruction of old red blood cells
- Blood storage
- Hematopoiesis
Three Lines of Defense
- First: External barriers (skin)
- Second: Nonspecific immunity (external opeinings like mouth, ear, nose)
- Third: Specific immunity (specific immunity)
Nonspecific Immunity
- External barriers (skin)
- Phagocytosis (macrophages, neutrophils)
- Antimicrobial proteins
- Natural killer cells
- Inflammation
- Fever
Phagocytosis
◦ Neutrophils (leave vessels to enter inflamed tissue to destroy
pathogens)
◦ Macrophages that evolve from monocytes (congregate in areas
where microbial invasion is likely, such as the alveoli, liver, spleen,etc.)
Interferons
a cell that is infected by a virus releases interferon to
bind to non-infected cells, causing them to produce enzymes that
will prevent (interfere) with virus replication if they also become infected
Complement system
20 different proteins that circulate in an
inactive form until activated by bacteria or antibodies
Cellular (cell-mediated) immunity
Aims to destroy foreign cells or infected host cells
Humoral (antibody-mediated) immunity
Sends antibodies to mark pathogen for later destruction
B cells
Develop from stem cells in red bone marrow
Mature in bone marrow
Then travel to lymphatic organs and tissues
T cells
Develop from stem cells in red bone marrow
Mature in thymus gland
Then travel to lymphatic organs and tissues
Five classes of antibodies
◦ IgA
◦ IgD
◦ IgE
◦ IgG
◦ IgM
three classes of T cells
◦ Cytotoxic T cells: Carry out attack
◦ Helper T cells: Supportive role
◦ Memory T cells: For future infections
