Chapter 21 Flashcards
What is the function of arteries
They are vessels that carry blood away from the heart
What are the 3 layers that make up an artery
- Tunica International
- Tunica Media
- Tunica Externa
What is the thickest layer that makes up an artery
Tunica Media which consists of smooth muscle and elastic fibers
What are the two types of arteries
a. Elastic arteries:
- tunica media contains a higher proportion of elastic fibers
- the larger arteries ex. Aorta
- these propel blood towards smaller arteries
b. Muscular arteries:
- the tunica media contains a higher proportion of smooth muscle, this allows for vasoconstriction which helps direct blood flow
- ex. Sympathetic response - gastric arteries constrict which direct blood to skeletal muscle
- these arteries carry blood to the organs
What does vasoconstriction help with
Directing blood flow
What are vessels that transport blood to the capillaries
Arterioles
What vessel is
- composed of basement membrane and simple squamous epithelium (1 thin layer of cells)
- Connect arterioles to venules
- permits exchange of substances between the blood and tissue cells (via interstitial fluid)
Capillaries
What is Microcirculation
flow of blood through the capillaries
In what direction do veins transport blood
Toward the heart
True or false:
Veins have the same 3 layers as an artery
True:
contains the same three layers as arteries, less smooth muscle is present
- the lumen is larger (greater surface area) than the corresponding artery
- contain valves to prevent the back flow of blood (these valves are folds of tunica interna that project into the lumen, muscular action helps move blood towards the heart)
What is it called when you have weakened valves that cause veins to become dilated and twisted
Varicose veins
What is a Hemorrhoid
varicosity of a vessel around the anus
Term describing the joining together of vessels (provides collateral circulation)
Anastomoses
Under normal circumstances, how much blood do veins and venules contain in comparison to the whole body supply
60% of the blood supply
What is Capillary Exchange
the movement of substances between the blood and interstitial fluid
Why is diffusion important for capillary exchange
provides movement for substances like oxygen, carbon dioxide, glucose, amino acids and some hormones
What does Transcytosis do in relation to capillary exchange
larger substances (like insulin) pass through the capillary wall via endocytotic vesicles
What is the process called Bulk Flow
a passive process where large numbers of dissolved and suspended particles in a fluid move together in the same direction
What two processes make up bulk flow
a. Filtration - pressure driven movement of fluid and solutes from the capillaries into interstitial fluid.
b. Reabsorption (Resorption) - pressure driven movement from interstitial fluid into capillaries.
What is BHP = blood hydrostatic pressure
the pressure generated by the pumping action of the heart
What does IFOP stand for
interstitial fluid osmotic pressure
What is BCOP = blood colloid osmotic pressure
the force caused by colloidal suspension of large particles in the interstitial fluid
What is IFHP = interstitial fluid hydrostatic pressure -
The pressure (B.P) in the capillaries decreases as blood moves through the capillaries.
What is the determining factor for the direction of bulk flow.
NFP = (BHP + IFOP) - (BCOP - IFHP)
What does “edema” represent
An abnormal increase in interstitial fluid volume
What are Hemodynamics
factors affecting blood flow
What is the definition of
Blood Flow
The volume of blood that flows through any tissue in a given period of time. Determined by the force of the heartbeat and the resistance through the body.
What is a Pulse (physically speaking)
The expansion and elastic recoil of arteries after systole of the left ventricle.
Is the pulse best felt in arteries closer or farther from the surface of the skin
Closer to the surface
What is Tachycardia and what is the range of BPM
Rapid heart rate. >100 b.p.m
What is Bradycardia and what is the range of BPM
Slow resting heart rate. <60 b.p.m
What is Systolic BP -
The force in the vessels during ventricular systole
What does Diastolic mean
The pressure remaining in the vessels during ventricular diastole.
What are the levels for systolic and diastolic hypertension
- Systolic > 140 mmHg
- Diastolic > 90 mmHg
What is the difference between hypertension and secondary hypertension
Secondary has an identifiable underlying cause.
ex. Renal hypertension assoc. with decreased blood flow through the Kidneys
Hypertension itself has an unknown cause
What is Vascular Resistance -
the opposition of blood flow due to friction between the blood and the walls of the blood vessels.
What are the associated factors of vascular resistance
Associated factors:
a.Size of lumen
b.Blood viscosity
c.Length of vessel(s)
What is Venous Return
The pressure difference between the venules (16 mmHg) and the right Atrium (0 mmHg) (The volume of blood flowing back to the Heart through systemic veins/)
What are the primary mechanisms of action for Venous Return
Skeletal muscle pump and Respiratory pump are the primary mechanisms of action.
Where is the cardiovascular center located and what is its primary function
located in the Medulla Oblongata, helps regulate stroke volume and heart rate
What are two receptors that respond to pressure and chemical changes
Baroceptors and chemoceptors
What hormones do the kidneys release when BP is low
Renin which leads to the production of Angiotensin II
What is autoregulation of blood pressure
Results from the tissue ability to automatically adjust to blood flow
What does aldosterone increase
Sodium absorption in the kidneys which increases bp
What does the antidiuretic hormone cause in terms of its effects on the blood vessels
Vasoconstriction and reabsorption of water by the kidneys
What results from the tissues ability to automatically adjust to blood flow
Autoregulation of Blood pressure
What are the physical changes that happen to blood vessel in relation to our body temperature
Warming: vasodilation
Cooling: vasoconstriction
What is the simple definition for “shock” in the cardiovascular system
failure of the cardiovascular system to deliver adequate oxygen and nutrients to meet cellular metabolic needs.
How much blood is lost in order to cause mild shock
10%-20% blood volume
What happens during mild shock
a. Activation of the Renin-Angiotensin-Aldosterone System
b. Secretion of ADH
c.Sympathetic stimulation, i.e. vasoconstriction, increased heart rate
d. Release of local vasodilators (to try to bring blood/nutrition to deprived cells)
