Test 4 Study Guide Part 2 Flashcards
What is the predominant force which moves water out of the capillaries?
Which part of the capillary is where this occurs?
Blood pressure (hydrostatic pressure) Closer to the arteries, before blood pressure falls later (from fluid loss)
What is the predominant force driving the return of blood into the capillaries?
Where?
Osmotic pressure
At the venous end of the capillaries
Why does osmotic pressure eventually overcome hydrostatic pressure?
Osmotic pressure stays constant, but hydrostatic pressure drops as water flows outward (and as the lower resistance of the venous system is reached)
What level is hydrostatic pressure in the beginning of the capillary? The end?
Osmotic pressure?
37 mmHg -> 17 mmHg (fall in hydrostatic pressure) 25 mmHg (osmotic pressure is constant)
Net filtration pressure:
- Define terms in the equation
- Equation:
- Define terms in the equation Capillary hydrostatic pressure (CHP): blood pressure in capillary Interstitial fluid hydrostatic pressure (IFHP): blood pressure in interstitial fluid (normally much lower than CHP - Equation: Note: Positive = fluid out capillary Negative = fluid into of capillary BHP - IFHP
What keeps interstitial fluid pressure low?
- Hydrostatic:
- Osmotic:
- Hydrostatic:
Drained by lymphatic - Osmotic:
Low protein levels in interstitial fluid
Colloid:
- ability to stay in solution:
- ability to stay in solution:
Colloids do not settle out of a solution
Colloidal osmotic pressure define:
Osmotic Pressure resulting from molecules which never settle out of solution, and which cannot cross the capillaries (most proteins cannot cross readily)
What is the predominant contributor to colloidal osmotic pressure?
Albumin
Oncotic pressure:
Colloid osmotic pressure of the plasma (blood Colloid osmotic pressure) - interstitial fluid colloid osmotic pressure.
What size of molecules freely exit the capillaries?
Molecules around the size of glucose and ions (Na+)
What causes the lower interstitial conc. of proteins in capillaries?
Restricted filtration of proteins through capillaries
Starling forces:
- Define:
- List them:
- Define: Forces which dictate flow of water and molecules into or out of the capillaries - List them: Oncotic pressure Net Filtration Pressure
How could the capillaries be adapted to increase flow of fluid OUT of the capillaries?
If the precapillary sphincters are open blood flow to the capillaries will be great, and net filtration force will far exceed oncotic pressure
How could the capillaries be adapted to increase flow of fluid INTO of the capillaries?
If the precapillary sphincters are partially closed (they are ‘never’ completely closed) blood flow to the capillaries will be small, and oncotic pressure will far exceed net filtration pressure
Of the fluid that leaves the capillaries, how much returns?
What happens to the remaining fluid?
85% returns.
the other 15% flows through the lymphatic system into the subclavian veins
What is the single most reliable indicator of kidney disease?
Why?
Protein in the urine
Because the kidney is normally impermeable to plasma proteins, so protein in urine indicates damage
Edema:
- Causes:
High arterial blood pressure Venous obstruction Leakage of plasma protein into interstitial fluid Decreased plasma protein concentration Obstruction of lymphatic drainage
Why does high arterial blood pressure cause edema?
Increases net filtration pressure
Why does venous blockage cause edema?
- Example:
Increases net filtration pressure
- Example:
Compression of veins in pregnancy
Why does leakage of plasma protein into interstitial fluid cause edema?
- Example:
Lowers oncotic pressure (lower colloid osmotic pressure of the plasma, higher colloid osmotic pressure of the interstitial fluid)
- Example:
Inflammation and allergic reaction
Why does decreased plasma protein concentration cause edema?
- Example:
Lowers oncotic pressure (lower colloid osmotic pressure of the plasma)
- Example:
Kidney disease
Liver disease
Why does Obstruction of lymphatic drainage cause edema?
- Example:
Lower net filtration pressure (Increase interstitial fluid hydrostatic pressure due to failure to drain 15% of fluid which remains in interstitial fluid)
Myxedema:
A swelling of skin caused by hypothyroidism
What provides the driving pressure for glomerular filtration?
The left ventricle
Glomeruli:
Small balls of fenestrated capillaries in the kidney which filter the plasma.
Percent reabsorbed later in the kidney (after glomeruli):
- Water:
- Sodium:
- Glucose:
- Urea:
- Water: 99%
- Sodium: 99.5%
- Glucose: 100% (no glucose in urine)
- Urea: 44%
How does sympathetic innervation effect water balance in the body?
Increased sympathetic innervation of the heart is seen when blood volume is high.
Decrease sympathetic innervation of the renal artery is seen when blood volume is high. (causes vasodilation, increased blood flow to and increased fluid loss in the kidney)
This can also work in reverse
Understand how osmoreceptors and ADH regulation works in response to osmosis changes in the blood:
Know it!
Does excessive water consumption without the presence of salt result in a prolonged increase of blood pressure?
Why?
No.
Lowers blood osmolality -> expansion of osmoreceptors in the brain -> decreased ADH -> increased urination
Is water a diuretic?
Yes
Explain blood volume mediated (not osmoreceptor mediated) regulation of ADH secretion:
Rise in blood volume stimulates stretch receptors in left atrium, aortic arch, and carotid sinus -> increased firing of sensory neurons (in cranial nerves IX and X) -> ADH is inhibited by this firing -> increased urination
Atrial natriuretic peptide:
- Source:
- Effect:
- Source:
Stretch receptors in atrial wall cause release - Effect:
Increases excretion of salt and water in urine
Mineralocorticoid:
- Define:
- Predominant Mineralocorticoid:
- Define:
Excretions of the adrenal cortex which regulate mineral levels in the body - Predominant Mineralocorticoid:
Aldosterone
What does Aldosterone promote?
- What does ADH promote?
- Which keeps osmolality constant?
The reabsorption of salt and water, in proportional amounts. - What does ADH promote? The absorption of water only - Which keeps osmolality constant? Aldosterone
Juxtaglomerular Apparatus:
- Location:
- Secretes:
- In response to what?
- Location: Juxta = next to juxtaglomerular apparatus -> the apparatus next the the glomerulus - Secretes: Renin - In response to what? Blood volume and blood pressure are low
Renin does what?
Converts Angiotensinogen -> angiotensin 1
Where is angiotensin converting enzyme found?
the blood vessels in your lungs.
The Renin-angiotensin-aldosterone system:
Renin (low blood pressure) activates angiotensinogen -> angiotensin one (ACE converts angiotensin I -> angiotensin II -> aldosterone secretion (and multiple other effects)
Angiotensin Converting Enzyme do?
Converts Angiotensin 1 -> Angiotensin 2
What does angiotensin 2 do?
Stimulates vasoconstriction of arterioles (increase blood pressure)
Release of aldosterone by adrenal cortex
Stimulates thirst center of the hypothalamus
Extrinsic regulation:
Regulation due to autonomic nervous system or endocrine system
(example: angiotensin 2)
Sympathoadrenal system:
- Effect on cardiovascular system:
- Systems which vasoconstrict by norepinephrine:
- Systemic effect of epinephrine on cardiovascular system:
- Effect on cardiovascular system:
Increased heart rate, rise in blood pressure (from increased vasoconstriction) - Systems which vasoconstrict by norepinephrine:
Digestive tract, skin, and kidneys - Systemic effect of epinephrine on cardiovascular system:
Vasodilation of skeletal muscles
Parasympathetic nerve endings in artioles:
- Effect:
- Neurotransmitter:
- Innervation of blood vessels in:
- Effect: Cause vasodilation - Neurotransmitter: Always cholinergic - Innervation of blood vessels in: Digestive tract, external genitalia, and salivary glands
Which system, sympathetic or parasympathetic innervation, is more important for the regulation of blood pressure and blood flow?
Why?
Sympathetic.
It innervates more regions then the parasympathetic. It is always active at some level. If it disappears we see vasodilation, if it increases in intensity there is a corresponding increase in vasoconstriction
Autoregulation:
- Define:
- Two types:
- Which two organs normally use this?
- Define: Organ regulates blood flow to itself (maintains constant level) - Two types: Myogenic Metabolic - Which two organs normally use this? Brain Kidney
Myogenic regulation (blood flow):
- Define:
- An organ which uses it:
- Define:
Muscle expands when pressure falls, and constricts when pressure rises, likely due to stretch receptors. - An organ which uses it:
The brain
Coronary artery vasospasm:
- Define:
- Likely possible cause:
- Define:
Heart coronary arteries constrict and spasm (muscle becomes tight) blocking blood flow - Likely possible cause:
Alkaline state induced by hyperventilation. If you hyperventilation, you consume H+ from your blood stream, and become more alkaline.
Ca2+ competes for entrance with H+.
Less H+ means more Ca2+ in the cell, which can result in a vasospasm
Metabolic regulation (blood flow):
- Define:
- Which tissues use this:
- Define:
if a tissue has decreased oxygen, increased CO2, decreased pH, release of potassium and paracrine regulators it will cause vasodilation, allowing it to be washed away and more nutrients to take its place
(waste products) -> vasodilation -> waste products removed, nutrients brought in - Which tissues use this:
Seemingly all. IMPORTANT FOR BRINGING NUTRIENTS TO THE MUSCLES!
Tissue products that have accumulated cause vasodilation (if you cut of blood supply to a zone and later return it)
Result of increased metabolism of an organ.
Seen when skeletal muscles are active
Reactive hyperemia:
Active hyperemia:
