Ch 20_Exam 1: Blood Vessels Flashcards
Name the 3 main types of blood vessels.
- Arteries
- Veins
- Capillaries
The following describes what kind of blood vessel?
- Connection between arteries and veins
- Smallest vessels (1 cell thick)
- Diffusion occurs here
- Only have tunica intima
Capillaries
The following describes what kind of blood vessel?
- Carry blood away from heart
- Very thick to absorb pressure
Arteries
The following describes what kind of blood vessel?
- Carry blood too the heart
- Less pressure so not as thick
Veins
What are the 3 layers that make up arteries and veins?
- Tunica Intima
- Tunica Media
- Tunica Externa
The following describes what layer of blood vessel tunica?
- Middle layer made of smooth muscle
- Controls vasoconstriction and vasodilation
Tunica Media
The following describes what layer of blood vessel tunica?
- Connective tissue of collagen fibers
- For protection
Tunica Externa
The following describes what layer of blood vessel tunica?
- Endothelial layer continuous with epicardium
Tunica Interna
Which blood vessels have valves to prevent backflow?
Veins
Which blood vessels are meant to withstand the pressure of the heart beat?
Artery
If you feel a pulse, is the vessel a vein or artery?
Artery
Which vessel type is the site of exchange/diffusion?
Capillary
Name the 3 types of arteries from largest to smallest.
- Conducting
- Distributing
- Resistant
Describe conducting arteries.
- largest/elastic
- Can expand & recoil pending on volume of blood being pushed through (not to be confused with vasodialation/constriction)
- Pressure reservoir
- Ex. Aorta, pulmonary trunk, carotid
Describe distributing arteries.
- Branch off conducting arteries
- Smaller in diameter
- Pressure is lower than conducting
- These will perform vasodilation/constriction
- Ex. Brachial, femoral,
Describe resistant arteries.
- Branch off distributing arteries
- Smallest (of all arteries) are called aterioles
- Contain pre-capillary sphincter
- Circular muscles can contract and close a lumen
- Can stop blood flow to capillaries
- Major control point
- Don’t have names as they are too numerous
Which arteries can contain sensory detectors for blood pressure? Why?
The Carotid and Aorta to ensure that pressure is high enough.
T or F
Sensory detectors in the arteries make sure blood pressure doesn’t get too high.
False.
What are the 3 types of capillaries?
- Continuous
- Fenestrated
- Sinusoid
Describe continuous capillaries.
- Contain smooth and continuous endothelium
- Exchange through diffusion but limited to molecules that are small enough and allowed to pass through (semi-permeable)
Describe fenestrated capillaries
- Large pores in endothelial layer
- Pores allow other molecules to be exchanged
- Can still diffuse, but allows more due to pores
Describe sinusoid capillaries.
- Wide gaps in endothelial layer
- Allow large molecules/cells to be exchanged
- Meshlike
Capilary beds are a major _______ point.
control
Blood flow to any tissue is going to be controlled by…
pre-capillary sphincters found on the arteriole side of the capillary bed.
The three methods of capillary exchange are…
- Diffusion
- Transcytosis
- Filtration/Reabsorbtion
Explain capillary exchange through diffusion.
Simple laws of diffusion (pressure) drive molecules through the endothelial wall.
T or F
Capillary exchange via exocytosis is via passive transport.
False
Explain capillary exchange through filtration and reabsorbtion.
The slight pressure in the capillaries can force some fluid out of the capillaries (intersticial fluid) which is reabsorbed by small veins on the other side of the capillaries.
What are the three circulation patterns for capillary beds and explain the flow of each.
- Simple pathway: artery>capillary bed>vein
- Portal system: artery>capillary bed>portal vein>capillary bed>vein
- Anastomosis: Multiple blood vessels leading to a capillary bed (on arterial and veinous sides) that ensures tissues get blood required even if vessels are damaged
How is blood pressure defined and measured by?
The force exerted on the vessel wall by blood flow and is measured in mmHg
Why must the body maintain an adequate blood pressure?
To be able to deliver blood to tissues.
Blood pressure terms:
What is blood flow?
The volume of blood flowing to a particular region
Blood pressure terms:
What is perfusion?
Flow of blood per given volume
Blood pressure terms:
What is resistance?
Opposition to blood flow.
The amount of restriction blood flow is exposed to.
In systemic blood pressure, blood flows from _____ pressure to _____ pressure.
high to low
In measuring blood pressure, what do the two numbers represent?
The higher number is sistole. The amount of pressure exerted on contraction.
The lower number is diastole. The amount of pressure exerted on relaxation.
What is an ideal blood pressure measurement?
120/80
Is arterial or veinous blood flow measured when taking blood pressure?
Arterial
Blood pressure measurement is of the
a. Pulmonary circulatory system
b. Systemic circulatory system
b.
What is the formula for Pulse Pressure?
PP = Sistole - Diastole
What three ways is veins transport blood back to the heart?
Briefly explain each.
- Muscular pumps: Skeletal muscles around veins help push blood along
- Respiratory pumps: Diaphragm pushes on vena cava to push blood along
- Sympathetic vasoconstriction: Vascular smooth muscle contracts to move blood along
What three ways does the body regulate blood pressure?
- Local control
- Neural control
- Hormonal control
Blood pressure regulation:
Define Local control
This is done through autoregulation - the ability of tissues to control blood flow to themselves
Blood pressure regulation:
What are the two theories of autoregulation in Local control?
- Metabolic theory: low levels of O2 (hypoxia) and metabolic wastes build up will cause vasodilation and increased blood flow to the area
- Myogenic theory: smooth muscles can detect stretch from high pressure and constrict in response
Blood pressure regulation
What organ controls blood pressure within Neural control?
Medulla Oblongata
Blood pressure regulation
What systems regulate blood pressure in Neural control?
Central Nervous System/Autonomic Nervous System
via Sympathetic and Parasympatheic systems
Blood pressure regulation
In Neural control, the sympathetic nervous system _______ blood pressure.
Increases
Blood pressure regulation
In Neural control, the parasympathetic nervous system _______ blood pressure.
Decreases
Blood pressure regulation
In Hormonal control, hormones can cause _______ and _______ of blood vessels to control blood pressure.
vasoconstriction and dilation
Blood pressure regulation
In Hormonal control, hormones regulate _______ balance, which determines blood volume.
H2O
An increase in blood volume will cause a ________ in blood pressure.
increase
Why does dehydration lower blood pressure.
Because water is removed from system thus lowering overall blood volume.
Angiotensis II is a hormone that is a…
powerful vasoconstrictor
Aldosterone is hormone responsible for _______ and thus _______.
salt retention, water retention
ADDH is an _______ that is responsible for _______ retention.
anti-diuretic, water
Epinephrine, also known as _______ , effects _______.
adrenaline, vasoconstriction
Circulatory shock is when…
cardiac output is insufficient to meet your body’s needs.
Name the 3 types of Circulatory Shock and briefly explain each.
- Hypovolemic shock: too little blood volume that leads to low blood pressure and can be caused from loss of blood, burns and vomiting
- Vascular shock: extreme vasodilation whih leads to low blood pressure and anaphylactic shock. Can be caused by sunburns.
- Cardiogenic shock: functional heart failure.
