Quiz 2

Cardiology Overview, Capillaries (Microcirculation) and Lymph, Autonomic Cardiovascular, Vascular Control, Cardiac Mechanics, Ventricular Performance

What is a key concept for the anatomy of arteries

they are elastic and strong; have lots of smooth muscle

What is a key concept for the anatomy of veins

Barely any smooth muscle around a vein- floppy

How would you define arteries

muscular; which makes them dynamic (contraction and relaxation)

How would you define veins?

Floppy and slow “lakes” of blood. The principal concern is clotting or not clotting

How would you describe capillaries?

tiny and area of gas&chemical exchange. do NOT have smooth muscle around them

State the starling equation

Fluid flux = K[(P_c – P_i )– (capillary oncotic pressure- intersitial oncotic pressure)]

What controls the heart and the vessels?

The autonomic systemw

what are the components of the autonomic system

sympathetic and parasympathetic system (see-saw)

What components of the heart make up the cardiac electric cycle?

SA node, AV node, Bundle of His, Bundle branches and Purkinje fibers

In a cardiocyte’s action potential, what is the element that is very important

Ca2+

What does the Frank-Starling Relationship tell us

How “stretched” the left ventricle is when it is starting its pumping cycle. The more stretched above the optimal starting place, the worse it pumps

What is the equation for cardiac output

CO = SV x HR

Define capillaries

responsible for all the “exchange” between the blood and the tissues, like with oxygen and carbon dioxide

what are some characteristics of capillaries?

• Connect arterioles to venules

• No smooth muscle

• No innervation

• Do not constrict or dialate

Where does Edema occur

capillaries

why would we want low velocity in capillaries

to provide sufficient time for capillary exchange

Name the major methods of capillary exchange

1. Paracellular

2. Transcellular

What is paracellular exchange?

Pass thru fenestrations in capillary endothelial cells and leak thru space between endothelial cells

What is transcellular exchange?

Transcytosis using vesicles and diffusion

Why is the cross sectional area of vessels important?

The total cross-sectional area of capillaries (4500cm²) is very large compared to main arteries like the aorta (4.5cm²) because resistance goes down

Why do we want a decreased resistance

For blood flow to slowly go through capillary network to have time to deliver oxygen

In which exchange are molecules passed from a high gradient to a low gradient

Paracellular exchange

What is the process called when you take molecules from the lumen to the interstitium

Transcytosis

In the Starling Forces equation, what is represented by the filtration coefficient

K_f

This represents how readily fluid can move across the capillary wall (filtration)

K_f

How would you measure hydrostatic pressure gradient?

by subtracting the pressure of the interstitium from the pressure of the capillary

How would you measure osmotic pressure gradient

by subtracting the interstitial fluid oncotic pressure from the capillary oncotic pressure

Why does the capillary blood pressure drop over capillary length

because it travels to the venous side

What do you know about the pressure about the interstitial fluid

it is constant over the capillary length

What is true about the osmotic pressure gradient

the osmotic pressure is constant over the capillary length in both the capillary and interstitial fluid

In which direction does osmotic pressure flow

Fluid flows from low osmotic pressure to high osmotic pressure

What does osmotic pressure depend on

concentration of solute, not identity of solute

What does it mean if you have a positive net filtration

filtration out of the capillary

what does it mean if you have a negative net filtration

absorption into the capillary

What does it mean if a tissue more “leaky”?

More “holes” in the capillary

What are some instances that can change the K_f factor?

Infection

What leads to disassembly of cell junctions in capillary walls?

Inflammatory response to infection

What is one cause of edema

infection

What does inflammation do to net filtration?

Increases it out of the capillary and into the intersitium

When can you see peripheral edema

When tissues become swollen due to inflammation

What is the term used to describe excess fluid int he tissues

Edema

Increased/decreased hydrostatic pressure out of the capillary- like increased/decreased venous flow back to the heart can cause edema

increased; decreased

Increased/decreased oncotic pressure within the capillary- like increased/decreased albumin in the blood can cause edema

decreased; decreased

How does excess fluid drain back into the circulatory system in healthy individuals?

Through the lymphatic system

What can happen if there is a problem with lymphatic removal of excess fluid

edema

In patients that had a lymph node dissection in the tx of breast cancer, what is a tool that can help?

Increasing the pressure of the interstitium using compression garments and massage

If nutrition is poor, how can lymphedema be treated?

Increasing the oncotic pressure of the capillary which increases protein (albumin) concentration in the blood

Name the two division of the Peripheral Nervous System

1. Somatic Nervous System

2. Autonomic Nervous System

Describe the autonomic nervous system

Neurologically regulates bodily functions and is predominately unconscious and involuntary

Name the divisions of the autonomic nervous system

1. Parasympathetic nervous system

2. Sympathetic nervous system

What regions does the sympathetic region originate from

Paraspinous chain for ganglia from T1-L2

What regions does the parasympathetic region originate from

Cranial and sacral areas

What are some things that occur in the parasympathetic “tone”

• constricted pupils

• increased salivary production

• reduced heart rate

• constricted bronchia

What are some things that occur in the sympathetic “tone”

• dilated pupils

• decreased salivary production

• increased heart rate

• dialated bronchia

What neurotransmitter(s) is/are associated with parasympathetic NS?

Cholinergic- acetylcholine

What neurotransmitter(s) is/are associated with sympathetic NS?

Epinephrine and norepinephrine

What receptors are associated with parasympathetic NS?

• Muscarinic

• Nicotinic

What receptors are associated with sympathetic NS?

Alpha 1, Alpha 2, Beta 1, Beta 2

Where are nicotinic receptors principally found

IN the Central Nervous System (brain/spinal cord) and at neuromuscular junction

Where are muscarinic receptors found

throughout the body where parasympathetic input occurs

What do you call medications that cause xerostomia?

Anti-cholinergic

What is responsible for salivation via the parasympathetic system

muscarinic receptors

What does Pilocarpine do

An important muscarinic agonist used for treating xerostomia

What are muscarinic antagonists used for

COPD (lung disease)

What is the principal location of Alpha 1 and 2 recepts

Vascular smooth muscle

Which sympathetic receptor increases tone to raise resistance- vasoconstrict

Alpha 1

This receptor decreases tone to lower resistance - vasorelax

alpha 2

What receptor originates from the myocardial cells (heart)?

Beta 1

Beta 2 receptors originiate

in the smooth muscle including lung

This receptor increases rate and contractile force

Beta 1

Beta 2 receptors are responsbile for

relaxing smooth muscle (bronchodilation, vasoconstriction)

What are beta 1 and ½ Antagonists (beta blockers)?

common drugs used to decrease sympathetic tone (control heart rate like in heart failure, used for headache, performance anxiety)

What medications end in ~olol

Beta 1 and Beta1/2 antagonists (beta blockers)

What are beta 2 agonists

common drugs used to increase sympathetic tone for COPD (lung disease) and asthma

What do you call the medications for beta 2 agonists

SABA, LABA

Where are baroreceptors located

in the carotid sinus and aortic arch

What do baroreceptors do

send fibers to CNS to regulate ANS activity

In what scenario would your sympathetic activity be decreased and parasympathetic activity be increased

if your blood pressure is high

In what scenario would your sympathetic activity be increased and parasympathetic activity be decreased

if your blood pressure is low

What is the medical term for dizziness and light-headness when
standing?

Postural/Orthostatic hypotension

What is autonomic neuropathy?

Resting tachycardia is suggestive of ANS dysfunction

What is the purpose of the cardiovascular system?

1. To deliver oxygen and nutrients to tissues

2. To remove metabolic wastes

When would you see increased blood flow?

When the body’s demand and activity for oxygen requires it

What is cardiac output?

The amount of flow (~5mL/min) the heart can create, dependent on the volume within the ventricle at the start of contraction

What is the equation for Cardiac Output?

CO = SV * HR

How can we increase flow?

By increasing HR and venous return to the heart

This process is the starting volume of the next contraction

Venous return

What is occuring on the arterial side of capillaries

flow is created by the pumping heart and regulated by the smooth muscles around the arterial vessels

What is occurring on the venous side of the capillary?

blood has passed through the capillaries and there is much less pressure compelling the blood forward

Name some ways how we can increase our cardiac output

skeletal muscle pumps, inspiration, sympathetic innervation to veins (which are much less dynamic than arteries)

this process increases thoracic volume which decreases pressure within the thorax

inspriation

what does decreased pressure do/move the blood

"pulls” the blood into the vena cava (which is expanded along with the thoracic expansion)

what do you see in increased venous tone

venous return is increased due to higher flow

What is the Poiseuille equation?

the relationship between flow, pressure, and resistance —> Q = dP/R

Describe the Poiseuille equation

flow is equal to change in pressure over resistance

How does pressure affect flow

it moves from higher pressure to lower pressure (P_arteriole-P_venous)

What is systolic BP

pressure when the heart contracts (arteries expand)

What is diastolic BP=

pressure when the heart relaxes (arteries recoil)