Blood Vessels Flashcards
What are the 3 layers of vessel walls from innermost to outermost?
- Tunica interna
- Tunica media
- Tunica externa
What type of tissue is tunica interna compose of?
Simple squamous epithelium + thin layer of connective tissue
Which layer of the vessel wall is the thickest?
Tunica media
Why layer of the vessel wall attaches vessel to surrounding connective tissue?
Tunica externa
What is the tunica media composed of?
Elastic fibers + smooth muscle
____ carry blood away from the heart
Arteries
____ carry blood towards the heart
Veins
Walls of arteries are ____ than veins
thicker
What are the 3 types of arteries?
- Elastic arteries
- Muscular arteries
- Arterioles
Arterioles carry blood from ____ arteries to the capillaries
muscular
Tunica media of arterioles have ____ smooth muscle
less
Arterioles branch further into:
metarterioles
What are capillary beds?
Networks of capillaries that connect metarterioles to venules
What is the opening of each capillary controlled by?
Precapillary sphincter
Is the precapillary sphincter solely locally controlled?
No
Where can capillaries be found?
Near every cell in the body but ore extensive in highly active tissue (muscle, liver, kidneys, brain)
Where can capillaries not be found?
Epithelia, cornea and lens of eye, cartilage
What are the 3 types of capillaries
- Continuous
- Fenestrated
- Sinusoids
What is the difference between the 3 types of capillaries?
- Continuous (no holes)
- Fenestrated (some holes)
- Sinusoids (many holes)
What are 4 mechanisms through which exchange in capillaries can occur>
- Hydrostatic pressure
- Diffusion across endothelial cells
- Diffusion through gaps in endothelium
- Diffusion through pores
Venules carry blood from ____ to larger ____
capillaries, veins
Venules lack tunica ____
media
How do veins counteract the fact that BP is too low to overcome gravity?
Venous valves and skeletal muscle pump the blood back to the heart
____ contain 2/3 of the total blood volume in the body while ____ and ____ contain 1/3
Veins, arteries, capillaries
Rate of blood flow is ____ proportional to pressure gradient and ____ proportional to vascular resistance
directly, inversely
Rate of blood flow is directly proportional to ____ ____ and inversely proportional to ____ ____
pressure gradient, vascular resistance
What is peripheral resistance?
Measure of opposition of blood flow through a vessel
What are the 3 things resistance id dependent on?
- Blood viscosity
- Vessel length
- Vessel radius
What is arterial blood pressure?
Force exerted by blood against a vessel wall
What are 2 things BP is dependent on?
- Volume of blood
- Compliance of vessel walls
What is systolic pressure?
Peak pressure exerted by ejected blood against vessel walls during systole
What is diastolic pressure?
Minimum pressure in arteries when blood is draining
What is the average BP?
120/80
What is pulse pressure?
Pressure difference between systole and diastole
What is mean arterial pressure (MAP)?
Average pressure responsible for driving blood forward into the tissues throughout cardiac cycle
How do you 2 ways calculate MAP?
- Diastolic pressure + 1/3 pulse pressure
- Cardiac output x total peripheral resistance
Describe vasodilation
Enlargement in circumference + radius of vessel
Describe vasoconstriction
Narrowing of vessel
What is the baroreceptor reflex?
Monitoring of BP
What is hypertension?
BP > 140/90
What is hypotension
BP < 100/60
What are the 2 types of hypertensions?
- Primary hypertension
- Secondary hypertension
What are 4 potential causes of primary hypertension
- Defective salt management in kidneys
- Excessive sale intake
- Family history
- Lifestyle behavior
What are 2 examples of secondary hypertension?
- Renal hypertension
- Endocrine hypertension
What are 2 potential causes of hypotension?
- Insufficient blood to fill vessels
- Heart too weak to pump blood
What is orthostatic (postural) hypotension?
Transient hypotensive condition due to inability to respond to gravitational shifts
What is edema?
Abnormal increase in interstitial fluid
What are 2 potential causes of edema from excess filtration?
- Increased BP in hydrostatic pressure at arteriolar end
- Increased permeability of capillaries
What is 1 potential cause of edema from inadequate reabsorption?
Decrease concentration of plasma proteins
What are the 2 arteries that branch off the ascending aorta?
Left & right coronary arteries
What are the 3 vessel branching off the aortic arch?
- Brachiocephalic trunk
- Left common carotid
- Left subclavian arteries
What does the brachiocephalic trunk divide into?
Right common carotid and right subclavian artery
What 2 aortas branch off the descending aorta?
Thoracic & abdominal aorta
What does the abdominal aorta branch into?
Left & right iliac arteries
Where are 7 potential pulse taking sites?
- Carotid
- Brachial
- Radial
- Femoral
- Popliteal
- Dorsalis pedis
- Posterior tibialis
What is a venipuncture?
Puncturing of veins for blood draws or IV starts
How does blood flow to the placenta?
Umbilical cord through umbilical arteries
How does blood return from placenta?
Umbilical vein that drains into ductus venosus
What is the foramen ovvale?
Interatrial opening
What is the ductus arteriosus?
Vessel connecting pulmonary trunk to aorta
What is a major cardiovascular change at birth?
When a newborn breathes for the first time, the lungs expand
What is patent foramen ovale?
Blood recirculates through pulmonary circuit instead of entering left ventricle
What is patent ductus arteriosus?
Rise in pressure in pulmonary circuit
What is ventricular septal defect?
Openings in interventricular septum
What is transposition of great vessels?
Aorta is connected right ventricle, pulmonary artery is connected to left ventricle
