Blood Flow / Blood Pressure ch 14

There are two basic mechanisms for regulating blood pressure: __________________________ mechanisms and ______________________ mechanisms.

Quick response slow response

2. ______________ enters the blood stream and converts the protein angiostenogen to angiotensin 1

Renin

Because vessel length remains relatively constant under normal circumstances this is not a major factor to changes in blood pressure. Obesity causes ____________ resistance as the total length of the body's blood vessels increases to supply the adipose tissue.

increased

The smaller the diameter the ________________ the resistance. Of all the factors that affect blood flow, the diameter of the blood vessel has the greatest effect. The body controls blood flow to specific areas to the body by controlling the ________________ of arterioles servicing those area.

greater Diameter

The longer the vessel the _________ the resistance. Blood "rubs" against the lining of the vessel as it flows past so the longer the total length of all the body's blood vessels, the _____________ the blood pressure must be to push the blood.

greater Higher

Pulse rate: = ______ rate

heart

________________________ mechanisms: Regulate vessel diameter, heart rate and heart contractility.

Quick response

Example: In skeletal muscle capillaries, the arterial end of the capillary has ______ mm Hg, which favours fluid moving ____. At the venous end of the capillary there is a _________ mm Hg, which favors fluid moving ____________ the capillary.

+11, out -9, into

Endocrine System Control: Epinephrine, Norepinephrine, Antidiuretic Hormone and Angiotensin II Epinephrine and norepinephrine are hormones secreted by the ____________________________ in response to sympathetic stimulation and have a significant effect on the diameter of blood vessels. _______________________ combines with alpha-1 receptors to produce general vasoconstriction, similar to __________ nervous system released norepiniphrine. _________________ combines with both alpha1 and beta2 adrenergic receptors but has a greater affinity for ___________ receptors

Adrenal medulla Norepinephrine sympathetic Epinephrine, beta2

_________________: Stimulates kidneys to reabsorb salt (Specifically Na+). Retention of salt causes an increase in ___________ Also increases ______________________ but, unlike ADH, it does not produce a change in plasma osmolality because salt and water are reabsorbed in proportional amounts.

Aldosterone water sre-absorption. Blood Volume

3. ____________________________ is converted to ______________________ by an angiotension-converting enzyme (ACE) as it passes through the capillaries of the lungs. Thus, conditions of ___________________________, ___________________________, and ______________________ cause increased production of angiotensin II in the blood.

Angiotensin I Angiotensin II Salt Deprivation, low blood volume, low blood pressure.

________________________: Part of the renin-angiotensin-aldosterone system. Regulates salt balance in blood plasma by controlling amount of salt retained by the kidneys and thus water retention. Is a potent vasoconstrictor - will discuss details later.

Angiotensin II

Hormones that regulate blood volume in the kidney include: ________________________, __________________, ___________________________________________________________

Antidiuretic Hormone (ADH) Aldosterone Renin-Angiotensin-Aldosterone system

____________________________: Released by posterior pituitary gland, a potent vasoconstrictor at high concentrations. Regulates ________ in blood plasma by controlling amount of water retained by kidneys - will discuss details later.

Antidiuretic hormone (vasopressin) water balance

When used without further specification, "blood pressure" usually refers to the ___________ pressure in the systemic circulation.

Arterial

Arterioles offer the most resistance to blood flow and thus help regulate ______________ blood pressure and _____________________

Arterial blood pressure Tissue perfusion

Sum of all the forces acting to move out of and into the capillary you find that there is an overall net movement of fluid out of the capillary at the _____________________ and an overall net movement of fluid into the capillary at the ______________________.

Arterial end Venous end

___________________: Smooth muscle controls vasoconstriction and vasodilation, innervated by ____________ nerves, respond to local chemical changes, hormones, and mechanical factors such as stretch (pressure)

Arterioles Sympathetic

Extrinsic controls of blood flow: Control of arteriolar diameter by both the ____________________________ system and the _________________ system.

Autonomic nervous, Endocrine

___________________________ are specialized sensory neurons in the walls of the aortic arch and the carotid sinuses (dilations of the carotid arteries in the neck)

Baroreceptors (quick hint: Baro- means pressure, like barometer)

1. Decrease in _______________________ and/or a decrease in Na+ concentrations is sensed by specialized cells of the _____________________________________

Blood Pressure (BP) Juxtaglomerular apparatus.

__________________________ is the pressure exerted by circulating blood upon the walls of blood vessels.

Blood Pressure.

Changes in blood volume due to hemorrage, accident, or donating a pint of blood will lower __________________ and trigger processes to restore blood volume.

Blood pressure

Slow response regulation of blood pressure: Slow or long-term regulation of blood pressure is primarily accomplished by altering _____________________ and is mediated by the ________________ and the ___________________

Blood volume Kidneys, hypothalamus

BONUS Distribution of water between the interstital fluid and the blood plasma is determined at the __________________. Total body water: _____ L Intracellular compartment: __________ of total Extracellular compartment: ________ of total ________% as interstital, ________% as blood plasma.

Capillaries ~44 2/3 1/3 80% interstital, 20% blood plasma

____________________: Exchange sites between the blood and tissue fluid. Water, nutrients, wastes, signaling molecules, lipid-soluble materials, and gases are exchanged primarily by diffusion.

Capillaries.

______________________ pressure: Blood pressure within the capillaries. Hydrostatic pressure pushes fluid out of the capillary and into the interstital space by filtration. Pressure declines by ~50% from the arterial end of the capillary to the venous end of the capillary.

Capillary Hydrostatic

Four forces affect the movement of fluid at the capillary. List them.

Capillary Hydrostatic Pressure Capillary Colloid osmotic pressure Interstital fluid hydrostatic pressure Interstital fluid osmotic pressure.

____________________________________ pressure: Osmotic pressure exerted primarily by plasma proteins (mainly ________________). Is significantly greater than the colloid osmotic pressure of interstital fluid. Opposes __________________________ pressure.

Capillary colloid osmotic Albumin Capillary hydrostatic

The increase in blood flow to skeletal muscles during exercise is mediated by three factors: 1 - An increase in _____________________ 2 - Vasodilation of _____________ 3- Vasoconstriction of arterioles in __________

Cardiac output Skeletal Muscle Arterioles viscera/skin

________________ shock: Weakened hearts failure to pump blood adequately.

Cardiogenic

________________ arterioles do not have alpha-1 receptors and are almost entirely controlled by __________ mechanisms that maintain a constant blood flow.

Cerebral Local

________________________ occurs when blood pressure falls so low that adequate blood flow to the tissues can no longer be maintained. Four main types: List them.

Circulatory Shock Hypovolemic Cardiogenic Vasogenic Neurogenic

Complications of hypertension: There are a bunch so just list em baby

Congestive heart failure Stroke Heart attack spontaneous hemmorhage renal failure retinal failure

Mean arterial pressure (MAP) is the blood pressure that is monitored and regulated in the body and consists of a number of factors as indicated by the diagram

DIAGRAMMM

The QUICK response of LOWERED BLOOD PRESSURE: The medulla oblongata reponds by: _________________ parasympathetic activity _________________ sympathetic activity, which 1. Increases heart rate and force of contraction 2. Causes vasoconstriction of arterioles 3. Stimulates adrenal glands to release the hormones epinephrine and norepinephrine, which enhances ________________, _____________, and _________________

Decreased Increased Heart rate, contractility, vasoconstriction

Mean arterial pressure (MAP) = ________________________________________________ Primary determinants: ______________ ______________ (hint: two things on your MAP sheet)

Diastolic pressure + 1/3 pulse pressure. Cardiac output total peripheral resistance

______________: Excessive accumulation of interstital fluid. Disturbance in the capillary and/or problems with lymphatic drainage.

Edema

An increase in venous return leads to an increase in _____________________________, which in turn, causes an increase in _______________

End-diastolic volume (EDV) Stroke volume (Frank Starling effect)

^ CONTINUED - Increased _________ production, which can be used clinically to increase blood flow to an area. Conversely, applying ice packs to an inflamed area produces __________________, which reduces swelling. - Increase in blood flow eventually lowers the levels of ___________ thus removing the stimulus for _______________ and the arteriole returns to its original diameter.

Heat, vasoconstriction Metabolites, vasodilation

The vascular tone of arterioles found in skeletal muscle is relatively ___________, consequently blood flow to resting muscles is low (20-25% of total blood blow). However, during heavy exercise, blood flow to the skeletal muscles ____________ significantly.

High Increases

Causes of edema: __________________________: Increases capillary pressure and causes excessive filtration. Hypertension

High arterial pressure

Clinical note: Local _____________ release dilates arterioles. - Not released in response to local metabolic changes and is not considered to control blood flow. - Tissue damage or allergic reactions cause ________ to be released from mast cells - Causes ________________ of arterioles and increases the blood flow into the area that produces redness and contributes to swelling.

Histamine histamine Vasodilation

_________________: Resting blood pressure above 140/90 mm Hg. Pre-hypertension is __________ Occurs in one of three adults. 2 broad classes: _____________ hypertension _____________ hypertension ________________: Resting blood pressure below 100/60 mmHg

Hypertension 120/80 Primary Secondary

Clinical application: ACE inhibitors __________________ (High blood pressure) can be treated with angiotensin converting enzyme inhibitors that: Block the formation of _________________, thus reducing its vasoconstrictor effect. Increase activity of _______________, a chemical that promotes vasodilation which decreases ____________________________. Good for treatment of ____________ since TPR is decreased

Hypertension Angiotensin II Bradykinin total peripheral resistance (TPR) congestive heart failure

___________________: Resting low blood pressure, occurs when: there is too little blood to ____________ Heart is too ____________

Hypotension fill the vessels. weak to drive the blood.

Antidiuretic hormone: Synthesized by the ______________________ and released by the ______________ lobe of the __________________________. Released in response to increased plasma concentrations (_________________) that can be due to dehydration or by excessive salt intake. Acts to increase blood ___________ and ________.

Hypothalamus Posterior, Pituitary Gland Osmolality volume and pressure.

________________ shock: Caused by severe hemmorhage or through loss of fluids (severe diarrhea, excessive urination, extensive sweating)

Hypovolemic

Causes of edema: _________________________: Produces a congestive increase in capillary pressure - ___________________ (Thrombus forms in a vein) - __________________ (Mechanical compression of veins) - _____________________ (Blood pulls in veins) - Congestive heart failure

Increased venous pressure Thrombosis Pregnancy Varicose veins

The QUICK response of ELEVATED BLOOD PRESSURE: The medulla oblongata responds by: __________________ parasympathetic activity (________ Nerve) which lowers ______________. ____________________ sympathetic activity (_______________Nerve) which reduces heart rate and force of contraction, and increases the diameter of the arterioles. Remember that decreased sympathetic activity dilates arteriolar diameter.

Increased, Vagus Nerve Heart rate Decreased, Cardiac nerves

__________________________ pressure: Promotes fluid movement into the interstital space from the capillary. Relatively low due to the low protein content of interstital fluid. Can be neglected (____ mmHg)

Interstital Fluid Osmotic

____________________________________ pressure: Hydrostatic pressure within the interstital fluid. Promotes fluid movement into the capillary from the interstital space

Interstital fluid hydrostatic

______________________: ability of an organ to regulate its own blood flow regardless of what may be happening elsewhere in the body.

Local control

The most important factor governing flow of blood to exercising muscles is ____________________________ (Active hypermia). As muscular activity increases, metabolites build up and directly induce the ____________ of local arterioles. Additionally, ____________________ stimulation by epinephrine causes vasodilation of arterioles in skeletal and cardiac muscles.

Local metabolic control vasodilation beta-andrenergic (Beta2 receptors)

Capillary blood pressure is relatively _______. This is advantageous because capillaries are fragile and high BP could cause them to burst. Capillaries are very ____________ and high BP could cause excess fluid loss.

Low Permeable

____________________________ functions to drain excess interstital fluid and proteins and return it back to the vascular system.

Lymphatic

Juxtaglomerular apparatus contains: _____________________________ cells located at the top of the ascending limb of the renal tubule, function to monitor Na+ concentration of ______________. __________________________ cells are modified smooth muscle cells located in the wall of the afferent arterioles. Function as ___________________ to sense changes in blood volume or pressure and secrete the enzyme ______________.

Macula densa tibular filtrate Juxtaglomerular cells (granular cells) Baroreceptors, renin

_____________________________ is the main driving force for propelling blood to the tisuses and must be closely regulated. Must be high enough for the brain and other organs to recieve adequate flow. Must be low enough so that it doesnt damage small blood vessels or create extra work for the heart.

Mean Arterial Pressure

_____________ shock: Loss of sympathetic vascular tone leads to generalized vasodilation. Can be caused by damage to ______ nervous system or excruciating pain.

Neurogenic central

The following factors produce vasodilation of arterioles in response to increased metabolic activity: * Decreased levels of __ *Decreased levels of CO2 and ____________ - Increased ________________, ______________ and ________________ release - Increased ______ in tissue fluid due to repeated action potentials that outpace the ability of the Na+/K+ pump to restore the resting membrane gradients of active muscle and neural tissue

O2, lactic acid Adenosine, Prostaglandin, Nitric Oxide (NO2) K+

_____________________ hypotension: Transient hypotensive condition resulting from insufficient compensatory responses to gravitational shifts in blood when person moves from horizontal to vertical position.

Orthostatic (postural)

______________________: Measure of solute concentration; the number of particles in a solution.

Osmolarity

Hypothalamus: Dehydration due to sweating, diarrhea, or excessive urine flow will cause an increase in __________________ of blood and a decrease in ____________________ and ____________

Osmolarity Blood volume and pressure

Fluid movement can be determined by the following: Expression to the left of the minus sign represents the sum of forces acting to move fluid _________ the capillary. Expression to the right represents the sum of forces acting on the capillary. It is a ______________ number at the arteriole end and a ___________________ number at the venular end.

Out of Positive Negative

Increased capillary permeability allows leakage of __________________ into the interstital fluid: Less _____________________________________ pressure to pull fluid back in.

Plasma proteins colloid osmotic capillary

Blood flow through vessels is affected by ______________ and __________________________________

Pressure Total peripheral resistance

____________________: Blood flows from an area of higher pressure to an area of lower pressure down a pressure gradient. _____________________ of the heart is the main driving force for blood flow through a vessel. The pressure in a vessel increases then the blood flow will ______

Pressure gradient Contraction increase.

_________________ hypertension accounts for 90% of cases. It is a catchall category where the underlying cause is unknown. Potential causes being investigated: Defects in _____ management by the kidneys. Excessive salt intake: Salt osmotically retains water thus raising ___________________. Diets low in K+ and Ca2+: Diets low in fruits, vegetables, and dairy. Plasma membrane abnormalities such as defective _____________ pumps which are crucial to salt management

Primary (essential Salt Plasma volume Na+-K+

____________ hypertension accounts for 10% of cases. -Occurs secondary to _______________. Examples: __________ hypertension: Could be due to atheroscleotic lesions protruding into the renal artery or external compression by a tumor that reduces blood flow through the kidney and thus blood pressure. Initiates the __________________________________________ pathway that promotes salt and water retention. _____________ hypertension: Pheochromocytoma is an adrenal medullary tumor that secretes excessive epinephrine and norepinephrine causing high cardiac output and peripheral vasoconstriction

Secondary another known primary problem. Renal rennin-angiotensin-aldosterone Endocrine

__________________________ mechanisms: Regulate blood volume.

Slow Response

Excessive RBCs result in __________ blood flow and ___________ blood pressure.

Slower Increased

Baroreceptors measure BP by monitoring the degree of _______________ in the vessel wall.

Stretch

Autonomic nervous system control: Arterioles are generally enervated only by the _____________________________ system. Parasympathetic innervation of arterioles is not significant except in the arterioles of ______________________ tissue. Sympathetic nerve fibers: Bond with _______________________ receptors on smooth muscles of blood vessels.

Sympathetc nervous Genital erectile (penis and clitoris) alpha-1 Adrenergic receptors

Arterioles servicing tissues at rest receive a baseline amount of ___________________ stimulation and thus are slightly constricted. This baseline level of constriction is called _________________________. Vasodilation is accomplished by decreasing sympathetic stimulation below baseline.

Sympathetic Vascular Tone

The Hypothalamus detects an increase in blood osmolarity and responds by: Activating the hypothalamic ___________________ to stimulate the individual to drink more water. Sends a signal to the posterior pituitary to release _____________________________, which increases the reabsorbtion of water into the collecting ducts of the kidney.

Thirst centers Antidiuretic hormone (ADH)

Stimulation of osmoreceptors produces sensations of _______________ and increased water intake, which increased ________________. ADH stimulates water reabsorption from the kidney filtrate and thus a _______________ volume of urine is excreted and maintains _________________________

Thirst, Blood Volume Smaller, Blood Volume.

Blood volume is regulated by: The exchange of fluid between capillaries and _______________ The kidneys: _______________________, and the ______________________________________

Tissues Antidiuretic hormone Renin-angiotensin-aldosterone system

______________________________: Resistance is the opposition to blood flow through a vessel. As resistance increases, then blood flow ________.

Total peripheral resistance decreases

Epinephrine can cause either vasoconstriction or vasodillation depending on the ______________________ found in the smooth muscle of a particular vessel. The binding of epinephrine to ________ receptors leads to vasoconstriction. Conversely, the binding of __________ receptors leads to vasodilation.

Type of receptor Alpha 1 Beta 2

Tonic sympathetic activity induces ______________________ (with the exception of those vessels in the brain) and ____________ blood flow to organs which results in elevating blood pressure.

Vasoconstriction reduces

4. Angiotensin II causes blood pressure and volume to rise by the following Blood pressure: Is a powerful __________________ of small arteries and arterioles which increases _____________/arteriol blood pressure. Blood volume: Stimulates the adrenal cortex to release _______________, a hormone that promontes Na+ and water retention at the kidneys and thus increases blood volume and BP. Stimulates ______ release by the posterior pituitary which increases blood volume and thus BP.

Vasoconstrictor total peripheral resistance Aldosterone ADH

________________ shock: Widespread vasodilation triggered by vasodilator substances - two types: __________ shock: massive infection - infectant releases vasodilator substances. ________________ shock: Extensive histamine release is severe allergic reaction.

Vasogenic Septic Anaphylactic

____________ refers to the friction developed between the molecules of the fluid as they slide over eachother. Primarily determined by the number of ________________. The greater the viscosity the greater the ________

Viscocity red blood cells resistance

Total peripheral resistance in the blood vessels is affected by three parameters: list them

Viscocity of the blood Length of the vessel Diameter or radius of vessel

As a result of _______________________ sympathetic stimulation, arterioles in the viscera and skin vasoconstrict during exercise. However, as exercise progresses and body temperature rises, cutaneous arterioles dilate in order to _______________ and reduce body temperature.

alpha-adrenergic radiate heat

Blood pressure varies depending on situation, ___________, and _________________

activity, disease status

Aldosterone secretion (by _______________________________) is stimulated by the Renin-angiotension-aldosterone system which is responsive to: Decreased _________________________ and reduced blood ______ and ___________

adrenal cortex Na+ concentrations volume and pressure.

Alpha-1 receptors are found in all __________ except brain/___________sinuses. Beta2 receptors are found predominantly in arterioles servicing ____________ muscle and ____________ muscle. Arterioles in digestive organs and kidneys, in contract, are equipped only with ________________________

arterioles/coronary Skeletal, heart alpha1

During a full-blown sympathetic response (fight or flight) the released epinephrine combine with ___________ receptors in the heart and skeletal muscle to reinforce local ___________________ mechanisms in these tissues. In the rest of the circulatory system (which has alpha1 receptors) epinephrine causes ______________.

beta2 vasodilation vasoconstriction

Local metabolic control: Matches ________ with organ needs. Arteriole diameter increases or decreases in response to the increased or decreased ______________ activity, respectively. Increased blood flow in response to enhanced tissue activity is called ________________________

blood flow Metabolic Active hyperemia (emia means blood)

Increased blood pressure causes baroreceptors to increase their rate of impulses being sent to the ____________________ of the medulla oblongata.

cardiac centers

The extent to which each organ actually recieves blood flow is determined by ____________________ adjustments that override the sympathetic contrictor effect. Therefore, each organ recieves the appropriate amount of blood dependent on its ____________ activity.

intrinsic (loca) arteriolar metabolic

Control of ateriolar vasoconstriction or vasodilation fall into two categories: 1. ____________ 2. ___________

intrinsic, extrinsic

Note: Skeletal and cardiac muscles have the most powerful _______________________ control mechanisms with which to override generalized sympathetic vasoconstriction.

local metabolic

Causes of edema: Obstruction of ________________________: Prevents return of excess interstital fluid. ___________: Filaria roundworm infection transmitted by mosquito. Causes _____________________, and roundworms block lymphatic drainage.

lymphatic drainage. Filariasis elephantiasis

It is regulated by the ____________ and ____________ systems and the ______________

nervous, endocrine kidneys

Causes of edema: Decreased ___________________________ concentration: Less capillary colloid osmotic pressure to pull fluid back in. - __________ disease (Decrease in albumin production - ___________ disease (excessive lossof proteins in urine) - _____________ (decrease in albumin production)

plasma protein Liver Kidney Starvation

5. High _________________, leading to high blood volume and pressure, inhibits ____________ secretion. Less aldosterone means ______ salt is retained by the kidneys and _____ is excreted in the urine.

salt intake renin less / more

Rising blood pressure causes the arterial walls to ____________ which stimulates the baroreceptors in the ________________________ and _________________

stretch Carotid Sinus, Aortic Arch

An increase in cardiac output: Exercise activates _________________ nervous system output to the heart causing an increase in HR and stroke volume. Exercise increases venous return of blood to the heart via the ___________________ pump and the _________________ pump.

sympathetic skeletal muscle pump, respiratory pump

Pulse pressure = Felt in an artery as the difference between ______________ and _________ pressure.

systolic - diastolic systolic, diastolic

Thirsty person drinks more, increased fluid intake causes an increase in blood __________________

volume and blood pressure.

The kidneys produce ____________ per day of blood filtrate. _____% of the filtrate is reabsorbed back into the vascular system. ____ of urine is excreted each day

~180 L ~98% ~1.5L

Formula bases: ___________ of the cardiac cycle is spend in diastole and only _________ in systole.

~2/3 ~1/3