Anatomy II Test One part 2

Question 1

Arteries
Capillaries
Veins

Answer 1

carry blood away from heart; oxygenated except for pulmonary circulation and umbilical vessels of fetus

contact tissue cells; directly serve cellular needs

carry blood toward heart

Question 2

Lumen

Three wall layers in arteries and veins

Capillaries

Answer 2

Central blood-containing space

Tunica intima, tunica media, and tunica externa

Endothelium with sparse basal lamina

Question 3

Vessels vary in

Answer 3

length, diameter, wall thickness, tissue makeup

Question 4

Lymphatic system

Answer 4

picks up extra interstitial fluid, drains into the subclavian veins

Question 5

Arterial System

Answer 5

Elastic Arteries
Muscular Arteries
Arterioles

Question 6

Elastic Arteries

Answer 6

Large thick-walled arteries with elastin in tunics
e.g. Aorta and its major branches
Large lumen offers low-resistance

Question 7

Muscular Arteries

Answer 7

Deliver blood to body organs
Thick tunica media with more smooth muscle
Active in vasoconstriction

Question 8

Arterioles

Answer 8

Smallest arteries
Lead to capillary beds
Control flow into capillary beds via vasodilation and vasoconstriction

Question 9

Capillaries

Answer 9

Walls of thin tunica intima
Diameter allows only single RBC to pass at a time
In all tissues except for cartilage, epithelia, cornea and lens of eye
Provide direct access to almost every cell
Functions
Exchange of gases, nutrients, wastes, hormones, etc., between blood and interstitial fluid

Question 10

Types of Capillaries

Answer 10

Continuous capillaries
Fenestrated capillaries
Sinusoid capillaries (sinusoids)

Question 11

Continuous Capillaries

Answer 11

Abundant in skin and muscles
Tight junctions connect endothelial cells
Intercellular clefts allow passage of fluids and small solutes
Continuous capillaries of brain unique
Tight junctions complete, no clefts, forms blood-brain barrier

Question 12

Fenestrated Capillaries

Answer 12

Some endothelial cells contain pores/windows (fenestrations)

More permeable than continuous capillaries

Function in absorption or filtrate formation (small intestines and kidneys)

Question 13

Sinusoid Capillaries

Answer 13

Very permeable
Few tight junctions; fenestrated; larger intercellular clefts; large lumens; incomplete basement membrane
Slow blood flow
Large molecules and blood cells can pass between blood and surrounding tissues
Found in the liver, bone marrow, spleen

Question 14

Capillary Beds

Answer 14

Microcirculation
Vascular shunt
Precapillary sphincters
True capillaries

Question 15

Microcirculation

Answer 15

Interwoven networks of capillaries between arterioles and venules

Question 16

Vascular Shunt

Answer 16

thoroughfare channel)

Directly connects terminal arteriole and postcapillary venule

Question 17

PreCapillary Sphincters

Answer 17

regulate blood flow into true capillaries

Question 18

True Capillaries

Answer 18

Branch off arteriole

Question 19

Venous System

Answer 19

Venules and Veins

Question 20

Venules

Veins

Answer 20

Formed when capillary beds unite
Consist of endothelium and a few pericytes

Formed when venules converge
Have thinner walls, larger lumens compared with corresponding arteries
Blood pressure lower than in arteries

Question 21

The following adaptations ensure blood returns to heart despite low blood pressure

Answer 21

Large-diameter lumens offer little resistance to blood flow
Venous valves prevent backflow of blood
Venous sinuses: flattened veins with extremely thin walls (e.g., coronary sinus of the heart and sinuses of the brain)

Question 22

Blood

Answer 22

Volume of blood flowing through vessel, organ, or entire circulation in given period
Measured as ml/min
Relatively constant when at rest
Varies widely through individual organs, based on needs

Question 23

Blood pressure (BP)

Answer 23

Force per unit area exerted on wall of blood vessel by blood
Expressed in mm Hg
Measured as systemic arterial BP in large arteries near heart

Pressure gradient provides
driving force that keeps blood moving from higher to lower pressure areas

Question 24

Resistance

Important Sources of Resistance

Answer 24

Opposition to flow
Measure of the amount of friction blood encounters with vessel walls, generally in peripheral (systemic) circulation

Blood viscosity
Total blood vessel length
Blood vessel diameter

Question 25

Factors that remain relatively constant

Answer 25

Blood viscosity | Blood vessel length

Question 26

Blood vessel diameter

Answer 26

Greatest influence on resistance Frequent changes alter peripheral resistance Vasoconstriction increases resistance Vasodilation decreases resistance Fatty plaques from atherosclerosis increase increase resistance

Question 27

Systemic Blood Pressure

Answer 27

Pumping action of heart generates blood flow Pressure results when flow is opposed by resistance Systemic pressure Highest in aorta Declines throughout pathway 0 mm Hg in right atrium Steepest drop occurs in arterioles

Question 28

Systolic pressure Diastolic pressure Pulse pressure Mean arterial pressure (MAP

Answer 28

pressure exerted in aorta during ventricular contraction lowest level of aortic pressure difference between systolic and diastolic pressure pressure that propels blood to tissues

Question 29

Factors Aiding Venous Return

Answer 29

Muscular pump Respiratory pump Venoconstriction

Question 30

Maintaining Blood Pressure Requires

Answer 30

Cooperation of heart, blood vessels, and kidneys | Supervision by brain

Question 31

Main factors influencing blood pressure

Answer 31

``` Cardiac output (CO) (= SV x HR) Peripheral resistance (PR) Blood volume ```

Question 32

Short-term mechanisms | Long-term renal regulation

Answer 32

Neural and Hormonal controls Counteract fluctuations in blood pressure by altering peripheral resistance and CO Kidney-mediated controls Counteracts fluctuations in blood pressure by altering blood volume

Question 33

Neural controls of peripheral resistance

Answer 33

Maintain MAP by altering blood vessel diameter If low blood volume all vessels constricted except those to heart and brain Alter blood distribution to organs in response to specific demands

Question 34

Neural controls operate via reflex arcs that involve

Answer 34

Baroreceptors Cardiovascular center of medulla Vasomotor fibers to

Question 35

Barorecptors Cardiovascular center of medulla Vasomotor fibers

Answer 35

Pressure sensors in Aorta and large arteries of neck and thorax Sympathetic neurons that alter CO and blood vessel diameter to heart and vascular smooth muscle Carry sympathetic signals from medulla

Question 36

Baroreceptor Reflexes

Answer 36

 blood pressure stimulates baroreceptors Baroreceptors send inhibitory signal to Cardiovascular Center Arterioles and venules dilate Cardioinhibitory center reduces HR and CO Blood pressure drops

Question 37

: Chemoreceptor Reflexes

Answer 37

Chemoreceptors in aortic arch and large arteries of neck detect increase in CO2, or drop in pH or O2 Cause increased blood pressure by Signaling cardioacceleratory center  increase CO Signaling vasomotor center  increase vasoconstriction

Question 38

Short-term Mechanisms: Hormonal Controls

Answer 38

Short term regulation via changes in peripheral resistance | Long term regulation via changes in blood volume

Question 39

Hormones that increase blood pressure Hormone that lowers blood pressure

Answer 39

Epinephrine and norepinephrine from adrenal gland  increased CO and vasoconstriction Angiotensin II stimulates vasoconstriction High ADH levels cause vasoconstriction Atrial natriuretic peptide causes decreased blood volume and vasodilation

Question 40

Long-term Mechanisms: Renal Regulation

Answer 40

Long-term mechanisms control BP by altering blood volume via kidneys Kidneys regulate arterial blood pressure Increased BP or blood volume causes elimination of more urine, thus reducing BP Decreased BP or blood volume causes kidneys to conserve water, and BP rises

Question 41

Monitoring Circulatory Efficiency

Answer 41

Vital signs: pulse blood pressure respiratory rate body temperature Pulse: pressure wave caused by the expansion and recoil of arteries Radial pulse (taken at the wrist) routinely used

Question 42

Systemic arterial BP

Answer 42

Measured indirectly using a sphygmomanometer Pressure is increased in the cuff until it exceeds systolic pressure in the brachial artery Pressure is released slowly and the examiner listens for Korotkoff sounds with a stethoscope 1st sound: systolic pressure at ~120 mmHg Sounds fade: diastolic pressure at ~80 mmHg

Question 43

Hypotension Orthostatic hypotension Chronic hypotension Acute hypotension

Answer 43

low blood pressure Systolic pressure below 100 mm temporary low BP and dizziness when suddenly rising from a sitting or reclining position hint of poor nutrition and warning sign for Addison’s disease or hypothyroidism due to circulatory shock

Question 44

Homeostatic Imbalance: Hypertension

Answer 44

Hypertension: high blood pressure 140/90 major cause of heart failure, vascular disease, renal failure, and stroke Primary hypertension – most common type 90% of hypertensive conditions Risk factors: heredity, diet, obesity, age, stress, diabetes mellitus, and smoking Secondary hypertension - less common Due to kidney disease, arteriosclerosis, and endocrine disorders

Question 45

Circulatory Shock

Answer 45

Any condition in which Blood vessels are inadequately filled Blood cannot circulate normally Results in inadequate blood flow to meet tissue needs Hypovolemic shock: due to large-scale blood loss Vascular shock: due to extreme vasodilation and decreased peripheral resistance Cardiogenic shock: due to inefficient heart unable to sustain adequate circulation