Ch.11: The Cardiovascular System Flashcards
1
Q
What is the cardiovascular system?
A
- A closed system of the heart and blood vessels
- The heart pumps blood
- Blood vessels allow blood to circulate to all parts of the body
2
Q
What are the functions of the cardiovascular system?
A
Transport oxygen, nutrients, cell wastes, hormones to and from cells
3
Q
What is the size of the heart?
A
Size of a human fist, weighing less than a pound
4
Q
What is the location of the heart?
A
Located in the thoracic cavity, between the lungs in the inferior mediastinum
5
Q
What is the orientation of the heart?
A
- Apex is directed toward left hip and rests on the diaphragm
- Base points toward right shoulder
6
Q
What is the pericardium?
A
A double-walled sac
7
Q
Fibrous pericardium is _____ and _____.
A
- Loose
* Superficial
8
Q
Serous membrane is deep to the fibrous pericardium and is composed of what two layers?
A
- Parietal pericardium: outside layer that lines the inner surface of the fibrous pericardium
- Visceral pericardium: next to heart; also known as the epicardium
9
Q
Serous fluid fills the space between the layers of pericardium, called the:
A
Pericardial cavity
10
Q
What are the layers of the walls of the heart?
A
Epicardium • Outside layer; the visceral pericardium Myocardium • Middle layer • Mostly cardiac muscle Endocardium • Inner layer known as endothelium
11
Q
What are the four chambers of the heart?
A
- Atria (right and left)
* Ventricles (right and left)
12
Q
What are the atria (right and left) of the heart?
A
- Receiving chambers
- Assist with filling the ventricles
- Blood enters under low pressure
13
Q
What are the ventricles (right and left) of the heart?
A
- Discharging chambers
- Thick-walled pumps of the heart
- During contraction, blood is propelled into circulation
14
Q
What is the interatrial septum?
A
Separates the two atria longitudinally
15
Q
What is the interventricular septum?
A
Separates the two ventricles longitudinally
16
Q
What are heart functions as a double pump?
A
- Arteries carry blood away from the heart
* Veins carry blood toward the heart
17
Q
What is a double pump?
A
- Right side works as the pulmonary circuit pump
* Left side works as the systemic circuit pump
18
Q
What is pulmonary circulation?
A
- Blood flows from the right side of the heart to the lungs and back to the left side of the heart
- Blood is pumped out of right side through the pulmonary trunk, which splits into pulmonary arteries and takes oxygen-poor blood to lungs
- Oxygen-rich blood returns to the heart from the lungs via pulmonary veins
19
Q
What is systemic circulation?
A
Oxygen-rich blood returned to the left side of the heart is pumped out into the aorta
• Blood circulates to systemic arteries and to all body tissues
• Left ventricle has thicker walls because it pumps blood to the body through the systemic circuit
Oxygen-poor blood returns to the right atrium via systemic veins, which empty blood into the superior or inferior vena cava
20
Q
Heart valves allow blood to flow in only _____, to prevent _____.
A
• One direction
all body tissues
• Backflow
21
Q
What are atrioventricular (AV) valves?
A
- Between atria and ventricles
- Left AV valve: bicuspid (mitral) valve
- Right AV valve: tricuspid valve
- Anchored the cusps in place by chordae tendineae to the walls of the ventricles
- Open during heart relaxation, when blood passively fills the chambers
- Closed during ventricular contraction
22
Q
What are semilunar valves?
A
- Between ventricle and artery
- Pulmonary semilunar valve
- Aortic semilunar valve
- Closed during heart relaxation
- Open during ventricular contraction
23
Q
Valves _____ and _____ in response to _____ in the heart.
A
- Open
- Close
- Pressure changes
24
Q
Blood in the _____ does not nourish the _____.
A
- Heart chambers
* Myocardium
25
The heart has its own nourishing circulatory system consisting of:
* Coronary arteries—branch from the aorta to supply the heart muscle with oxygenated blood
* Cardiac veins—drain the myocardium of blood
* Coronary sinus—a large vein on the posterior of the heart; receives blood from cardiac veins
26
Blood empties into the _____ via the _____.
* Right atrium
| * Coronary sinus
27
What is the intrinsic conduction system of the heart?
• Cardiac muscle contracts spontaneously and independently of nerve impulses
• Spontaneous contractions occur in a regular and continuous way
*Atrial cells beat 60 times per minute
*Ventricular cells beat 20−40 times per minute
*Need a unifying control system—the intrinsic conduction system (nodal system)
28
What are the two systems which regulate heart activity in the intrinsic conduction system of the heart?
• Autonomic nervous system
• Intrinsic conduction system, or the nodal system
*Sets the heart rhythm
*Composed of special nervous tissue
*Ensures heart muscle depolarization in one direction only (atria to ventricles)
*Enforces a heart rate of 75 beats per minute
29
Concept Link 1
This is very similar to the one-way generation of an action potential as it travels down the axon of a neuron like a wave (Chapter 7, p p. 234-236). The signals that stimulate cardiac muscle contraction also travel one way throughout the intrinsic conduction system.
30
What are the components of the intrinsic conduction system of the heart?
• Sinoatrial (SA) node
*Located in the right atrium
*Serves as the heart’s pacemaker
• Atrioventricular (AV) node is at the junction of the atria and ventricles
• Atrioventricular (AV) bundle (bundle of His) and bundle branches are in the interventricular septum
• Purkinje fibers spread within the ventricle wall muscles
• The sinoatrial node (SA node) starts each heartbeat
• Impulse spreads through the atria to the AV node
• Atria contract
• At the AV node, the impulse is delayed briefly
• Impulse travels through the AV bundle, bundle branches, and Purkinje fibers
• Ventricles contract; blood is ejected from the heart
31
What is tachycardia?
Rapid heart rate, over 100 beats per minute
32
What is bradycardia?
Slow heart rate, less than 60 beats per minutes
33
What is the cardiac cycle?
One complete heartbeat, in which both atria and ventricles contract and then relax
• Systole = contraction
• Diastole = relaxation
34
Average heart rate is approximately __ beats per minute.
75
35
Cardiac cycle length is normally __ seconds.
0.8
36
What is atrial diastole (ventricular filling)?
* Heart is relaxed
* Pressure in heart is low
* Atrioventricular valves are open
* Blood flows passively into the atria and into ventricles
* Semilunar valves are closed
37
What is atrial systole?
* Ventricles remain in diastole
* Atria contract
* Blood is forced into the ventricles to complete ventricular filling
38
What is isovolumetric contraction?
* Atrial systole ends; ventricular systole begins
* Intraventricular pressure rises
* AV valves close
* For a moment, the ventricles are completely closed chambers
39
What is ventricular systole (ejection phase)?
* Ventricles continue to contract
* Intraventricular pressure now surpasses the pressure in the major arteries leaving the heart
* Semilunar valves open
* Blood is ejected from the ventricles
* Atria are relaxed and filling with blood
40
What is isovolumetric relaxation?
* Ventricular diastole begins
* Pressure falls below that in the major arteries
* Semilunar valves close
* For another moment, the ventricles are completely closed chambers
* When atrial pressure increases above intraventricular pressure, the AV valves open
41
What are types of heart sounds?
* Lub—longer, louder heart sound caused by the closing of the AV valves
* Dup—short, sharp heart sound caused by the closing of the semilunar valves at the end of ventricular systole
42
What is cardiac output (CO)?
Amount of blood pumped by each side (ventricle) of the heart in 1 minute
43
What is stroke volume (SV)?
* Volume of blood pumped by each ventricle in one contraction (each heartbeat)
* About 70 milliliter of blood is pumped out of the left ventricle with each heartbeat
44
What is a typical heart rate (HR)?
Typically 75 beats per minute
45
Cardiac output is the product of the _____ and the _____.
* Heart rate (HR)
* Stroke volume (SV)
* CO = HR X SV
* CO = HR (75 beats/min) X SV (70 ml/beat)
* CO = 5250 ml/min = 5.25 L/min
46
What is regulation of stroke volume?
• 60 percent of blood in ventricles (about 70 milliliter) is pumped with each heartbeat
• Starling’s law of the heart
*The critical factor controlling S V is how much cardiac muscle is stretched
*The more the cardiac muscle is stretched, the stronger the contraction
• Venous return is the important factor influencing the stretch of heart muscle
47
What are the factors that modify basic heart rates?
* Neural (ANS) controls
* Hormones and ions
* Physical factors
48
How do neural (ANS) controls modify basic heart rates?
* Sympathetic nervous system speeds heart rate
| * Parasympathetic nervous system, primarily vagus nerve fibers, slow and steady the heart rate
49
How do hormones and ions modify basic heart rates?
* Epinephrine and thyroxine speed heart rate
| * Excess or lack of calcium, sodium, and potassium ions also modify heart activity
50
How do physical factors modify basic heart rates?
Age, gender, exercise, body temperature influence heart rate
51
Blood vessels form a closed vascular system that transports blood to the tissues and back to the heart
* Closed vascular system
* Tissues
* Heart
52
Vessels that carry blood away from the heart:
Arteries and arterioles
53
Vessels that play a role in exchanges between tissues and blood
Capillary beds
54
Vessels that return blood toward the heart
Venules and veins
55
What are the three layers (tunics) in blood vessels (except the capillaries)?
Tunica intima forms a friction-reducing lining
• Endothelium
Tunica media
• Smooth muscle and elastic tissue
• Controlled by sympathetic nervous system
Tunica externa forms protective outermost covering
• Mostly fibrous connective tissue
• Supports and protects the vessel
56
What are the structural differences in arteries, veins, and capillaries?
• Arteries have a heavier, stronger, stretchier tunica media than veins to withstand changes in pressure
• Veins have a thinner tunica media than arteries and operate under low pressure
*Veins also have valves to prevent backflow of blood
*Lumen of veins is larger than that of arteries
*Skeletal muscle “milks” blood in veins toward the heart
57
What is the structure of capillaries?
• Only one cell layer thick (tunica intima)
• Allow for exchanges between blood and tissue
• Form networks called capillary beds that consist of:
*A vascular shunt
*True capillaries
• Blood flow through a capillary bed is known as microcirculation
58
What is the structure of true capillaries?
* Branch off a terminal arteriole
* Empty directly into a postcapillary venule
* Entrances to capillary beds are guarded by precapillary sphincters
59
What is the aorta?
* Largest artery in the body
| * Leaves from the left ventricle of the heart
60
What are the regions of the aorta?
* Ascending aorta—leaves the left ventricle
* Aortic arch—arches to the left
* Thoracic aorta—travels downward through the thorax
* Abdominal aorta—passes through the diaphragm into the abdominopelvic cavity
61
What is the function of the arterial branches of the ascending aorta?
Right and left coronary arteries serve the heart
62
Brachiocephalic trunk splits into the:
* Right common carotid artery
| * Right subclavian artery
63
Left common carotid artery splits into the:
• Left internal and external carotid arteries
64
Left subclavian artery branches into the:
* Vertebral artery
| * In the axilla, the subclavian artery becomes the axillary artery → brachial artery → radial and ulnar arteries
65
What are the arterial branches of the thoracic aorta?
• Intercostal arteries supply the muscles of the thorax wall
• Other branches of the thoracic aorta (not illustrated) supply the:
*Lungs (bronchial arteries)
*Esophagus (esophageal arteries)
*Diaphragm (phrenic arteries)
66
What is the first arterial branch of the abdominal aorta?
Celiac trunk
67
What are the three arterial branches of the abdominal aorta?
1. Left gastric artery (stomach)
2. Splenic artery (spleen)
3. Common hepatic artery (liver)
68
Superior mesenteric artery supplies most of the _____ and first half of the _____.
* Small intestine
| * Large intestine
69
What are the arterial branches of the abdominal aorta?
• Left and right renal arteries (kidney)
• Left and right gonadal arteries
*Ovarian arteries in females serve the ovaries
*Testicular arteries in males serve the testes
• Lumbar arteries serve muscles of the abdomen and trunk
70
Inferior mesenteric artery serves the second half of the:
Large intestine
71
Left and right _____ are the final branches of the aorta.
Common iliac arteries
72
Internal iliac arteries serve the:
Pelvic organs
73
External iliac arteries enter the thigh → _____ → popliteal artery → _____
* Femoral artery
| * Anterior and posterior tibial arteries
74
_____ and _____ enter the right atrium of the heart
* Superior vena cava
* Inferior vena cava
* Superior vena cava drains the head and arms
* Inferior vena cava drains the lower body
75
Radial and ulnar veins → brachial vein → _____
Axillary vein
76
_____ drains the lateral aspect of the arm and empties into the _____.
* Cephalic vein
| * Axillary vein
77
_____ drains the medial aspect of the arm and empties into the _____.
* Basilic vein
| * Brachial vein
78
_____ and cephalic veins are joined at the _____.
* Basilic
| * median cubital vein (elbow area)
79
Subclavian vein receives:
* Venous blood from the arm via the axillary vein
| * Venous blood from skin and muscles via external jugular vein
80
_____ drains the posterior part of the head
• Vertebral vein
81
_____ drains the dural sinuses of the brain.
• Internal jugular vein
82
Left and right brachiocephalic veins receive venous blood from the:
* Subclavian veins
* Vertebral veins
* Internal jugular veins
83
Brachiocephalic veins join to form the superior vena cava → _____
Right atrium of heart
84
Azygos vein drains the _____.
Thorax
85
Anterior and posterior _____ veins and _____ veins drain the legs.
* Tibial
| * Fibial
86
Posterior tibial vein → _____ → femoral vein → _____
* Popliteal vein
| * External iliac vein
87
_____ receive superficial drainage of the legs.
Great saphenous veins (longest veins of the body)
88
Each common iliac vein (left and right) is formed by the union of the _____ and _____ vein on its own side.
* Internal
| * External iliac
89
_____ drains the right ovary in females and right testicle in males.
Right gonadal vein
90
Left gonadal vein empties into the:
Left renal vein
91
Left and right renal veins drain the:
Kidneys
92
_____ drains the digestive organs and travels through the liver before it enters _____.
* Hepatic portal vein
| * Systemic circulation
93
Left and right hepatic veins drain the:
Liver
94
Internal carotid arteries divide into:
* Anterior and middle cerebral arteries
| * These arteries supply most of the cerebrum
95
Vertebral arteries join once within the skull to form the:
* Basilar artery
| * Basilar artery serves the brain stem and cerebellum
96
Posterior cerebral arteries form from the division of the:
* Basilar artery
| * These arteries supply the posterior cerebrum
97
What is the result of anterior and posterior blood supplies. which are united by small communicating arterial branches?
Complete circle of connecting blood vessels called cerebral arterial circle, or circle of Willis
98
Hepatic portal circulation is formed by veins draining the digestive organs, which empty into the:
* Hepatic portal vein
* Digestive organs
* Spleen
* Pancreas
* Hepatic portal vein carries this blood to the liver, where it is processed before returning to systemic circulation
99
Concept Link 2
Like the portal circulation that links the hypothalamus of the brain and the anterior pituitary gland (Chapter 9, p. 313), the hepatic portal circulation is a unique and unusual circulation. Normally, arteries feed capillary beds, which in turn drain into veins. In the hepatic portal circulation, veins feed the liver circulation (Figure 11 .16).
100
What are vital signs?
Measurements of arterial pulse, blood pressure, respiratory rate, and body temperature
101
What is arterial pulse?
* Alternate expansion and recoil of a blood vessel wall (the pressure wave) that occurs as the heart beats
* Monitored at pressure points in superficial arteries, where pulse is easily palpated
* Pulse averages 70 to 76 beats per minute at rest, in a healthy person
102
What is blood pressure?
* The pressure the blood exerts against the inner walls of the blood vessels
* The force that causes blood to continue to flow in the blood vessels
103
Concept Link 3
As you remember, in the passive process of filtration, substances move from areas of high pressure to areas of low pressure through a filter (Chapter 3, p. 76). Blood flow is driven by these same differences in pressure, but without a filter.
104
When the ventricles contract in a blood pressure gradient:
* Blood is forced into elastic arteries close to the heart
| * Blood flows along a descending pressure gradient
105
Pressure _____ in blood vessels as distance from the heart _____.
* Decreases
| * Increases
106
Pressure is _____ in the arteries, _____ in the capillaries, and _____ in the veins.
* High
* Lower
* Lowest
107
What are the two arterial blood pressures are measured?
• Systolic—pressure in the arteries at the peak of ventricular contraction
• Diastolic—pressure when ventricles relax
• Expressed as systolic pressure over diastolic pressure in millimeters of mercury (m m H g)
*For example, 120/80 mm Hg
108
_____ method is an indirect method of measuring systemic arterial blood pressure, most often in the _____.
* Auscultatory
| * Brachial artery
109
Arterial blood pressure (BP) is directly related to _____ and _____.
* Cardiac output
* Peripheral resistance
* Cardiac output (CO; the amount of blood pumped out of the left ventricle per minute)
* Peripheral resistance (PR; the amount of friction blood encounters as it flows through vessels)
110
Parasympathetic nervous system has _____ on blood pressure.
Little to no effect
111
Sympathetic nervous system promotes _____, which increases _____.
* Vasoconstriction (narrowing of vessels)
| * Blood pressure
112
What are renal factors which affect blood pressure?
* Kidneys regulate blood pressure by altering blood volume
* If blood pressure is too high, the kidneys release water in the urine
* If blood pressure is too low, the kidneys release renin to trigger formation of angiotensin II, a vasoconstrictor
* Angiotensin II stimulates release of aldosterone, which enhances sodium (and water) reabsorption by kidneys
113
How does temperature affect blood pressure?
* Heat has a vasodilating effect
| * Cold has a vasoconstricting effect
114
How do chemicals affect blood pressure?
* Various substances can cause increases or decreases in blood pressure
* Epinephrine increases heart rate and blood pressure
115
Concept Link 4
Recall that epinephrine is the "fight-or-flight" hormone, which is produced by the adrenal medulla and helps us deal with short-term stress (Chapter 9, p. 323).
116
How does diet affect blood pressure?
Commonly believed that a diet low in salt, saturated fats, and cholesterol prevents hypertension (high blood pressure)
117
What is the normal range for blood pressure?
* Systolic pressure ranges from 110 to 140 mm Hg
| * Diastolic pressure ranges from 70 to 80 mm Hg
118
What is hypotension?
* Low systolic (below 100 mm Hg)
* Often associated with illness
* Acute hypotension is a warning sign for circulatory shock
119
What is hypertension?
* Sustained elevated arterial pressure of 140/90 mm Hg
| * Warns of increased peripheral resistance
120
Interstitial fluid (tissue fluid) is found between:
Cells
121
Substances move to and from the blood and tissue cells through:
* Capillary walls
* Exchange is due to concentration gradients
* Oxygen and nutrients leave the blood and move into tissue cells
* Carbon dioxide and other wastes exit tissue cells and enter the blood
122
Substances take various routes entering or leaving the blood, such as:
* Direct diffusion through membranes
* Diffusion through intercellular clefts (gaps between cells in the capillary wall)
* Diffusion through pores of fenestrated capillaries
* Transport via vesicles
123
Fluid movement out of or into a capillary depends on the difference between which two pressures?
1. Blood pressure forces fluid and solutes out of capillaries
2. Osmotic pressure draws fluid into capillaries
124
_____ is higher than _____ at the arterial end of the capillary bed.
* Blood pressure
| * Osmotic pressure
125
_____ is lower than _____ at the venous end of the capillary bed.
* Blood pressure
| * Osmotic pressure
126
Since blood pressure is higher at the arterial end and osmotic pressure is higher at the venous end of the capillary bed, fluid moves out of the capillary at the _____ of the bed and is reclaimed at the _____ end.
* Blood pressure
| * Osmotic pressure
127
In an embryo the heart:
* Develops as a simple tube and pumps blood by week 4 of pregnancy
* Becomes a four-chambered organ capable of acting as a double pump over the next 3 weeks
128
What is the function of the umbilical cord?
* Carries nutrients and oxygen from maternal blood to fetal blood
* Fetal wastes move from fetal blood to maternal blood
129
What does the umbilical cord house?
* One umbilical vein, which carries nutrient- and oxygen-rich blood to the fetus
* Two umbilical arteries, which carry wastes and carbon dioxide–rich blood from the fetus to placenta
130
_____ bypassing the lungs and liver are present in a fetus
• Shunts
• Blood flow bypasses the liver through the ductus venosus and enters the inferior vena cava → right atrium of heart
• Blood flow bypasses the lungs
*Blood entering right atrium is shunted directly into left atrium through foramen ovale (becomes fossa ovalis at or after birth)
*Ductus arteriosus connects aorta and pulmonary trunk (becomes ligamentum arteriosum at birth)
131
Age-related problems associated with the cardiovascular system include:
* Weakening of venous valves
* Varicose veins
* Progressive arteriosclerosis
* Hypertension resulting from loss of elasticity of vessels
* Coronary artery disease resulting from fatty, calcified deposits in the vessels
