Structures HR Flashcards
(87 cards)
1
Q
apex of the heart
A
is the pointed end of the heart, formed by the tip of the left
ventricle (lower chamber of the heart).
2
Q
base of the heart
A
is formed by the atria (upper chambers of the heart).
3
Q
Heart lies
A
2/3 of its mass lies to the left of the midline
4
Q
Two parts of the pericardium:
A
Fibrous pericardium
Serous pericardium
5
Q
Fibrous pericardium:
A
Tough, inelastic and outer connective tissue.
6
Q
Pericardium functions to protect the heart by:
A
(a) Anchoring in place (attached to the diaphragm).
(b) Prevents it from over stretching.
7
Q
Parietal layer:
A
Fused to the fibrous pericardium
8
Q
Visceral layer (epicardium):
A
Adheres tightly to the heart
9
Q
Made up of three layers: HR
A
Epicardium
Myocardium
Endocardium
10
Q
Epicardium
A
to include the visceral layer of the serous pericardium).
11
Q
Myocardium
A
Forms two separate networks via gap junctions and intercalated disks: Atrial
and ventricular.
Each network contracts as a unit.
12
Q
Endocardium
A
Lines inside of myocardium and covers valves.
13
Q
The heart is composed of four chambers:
A
Two atria [base] and two ventricles. [top]
14
Q
The two Atrioventricular (AV): Located between atria and ventricles.
A
(a) Tricuspid Valve (3 cusps).R
(b) Bicuspid (also known as Mitral) Valve (2 cusps). L
15
Q
Chordae tendineae
A
connect to papillary muscles (located on ventricle side).
(a) Prevent valve cusps from pushing up into the atria when ventricles contract.
16
Q
The Semilunar (SL) Valves, close secondary to a pressure change.
A
(a) Aortic Valve L
(b) Pulmonic Valve R
17
Q
Superior and Inferior Vena Cava
A
(1) Both drain deoxygenated blood from the upper and lower body into the right
atrium.
18
Q
Coronary Sinus
A
(1) Drains deoxygenated blood from the coronary veins into the right atrium.
19
Q
Pulmonary trunk and Pulmonary artery
A
(1) Blood is pumped from the right ventricle into the pulmonary trunk which then
branches into the pulmonary arteries that then carry this deoxygenated blood into
the lungs to be oxygenated.
20
Q
Pulmonary veins
A
(1) Carries oxygenated blood from the lungs and transports it to the left atrium.
(a) Left atrium empties into the left ventricle which then pumps blood into the
aorta.
21
Q
Aorta
A
Carries oxygenated blood to the entire body from the left ventricle.
22
Q
DESCRIBE how Blood Flows through the Heart.
A
Deoxygenated blood enters the heart via the superior and inferior vena cava or coronary sinuses, drains into the right atrium, empties into the right ventricle, then pumped to the lungs via the pulmonary trunk and left and right pulmonary arteries to be oxygenated.
After oxygenation, blood is pumped to the heart by the pulmonary vein into the left
atrium, which empties into left ventricle and is pumped through the body via the
aorta.
A constant, uninterrupted blood supply is essential for the heart’s function.
Blood flow through the myocardium is known as coronary circulation.
23
Q
There are two principal coronary vessels:
A
(a) Right coronary artery
(b) Left coronary artery
24
Q
coronary sinus
A
collects the heart’s deoxygenated blood and returns it to the right atrium.
25
Cardiac excitation normally begins in the sinoatrial (SA) node, and is then conducted
through:
(1) The atria (via Bachmann’s bundle) causing contraction.
(2) Atrioventricular (AV) node
(3) AV bundle branches (known as the bundle of his).
(4) Right and left bundle branches
(5) Purkinje fibers
26
How a wave form is created on electrocardiogram?
Waves on an ECG are created by placing electrodes on the skin to pick up the electrical current generated by the heart.
27
When reviewing an ECG recording three discernible waves will be noted:
(a) P wave: Representing atrial depolarization
(b) QRS Complex: Representing ventricular depolarization (masks atrial repolarization due to size).
(c) T wave: Representing ventricular repolarization
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A cardiac cycle represents everything associated with one heartbeat, typically lasting
0.8 seconds.
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P wave:
Representing atrial depolarization
30
QRS Complex:
Representing ventricular depolarization (masks atrial repolarization due to size).
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T wave:
Representing ventricular repolarization
32
Relaxation period;
the ventricles start to relax and repolarize (repolarization is indicated as the T wave on an EKG); all four chambers of the heart, including the atria enter into a period of diastole (dilation), during diastole, the ventricles are filled to 75%.
33
atrial systole
(contraction) both atria depolarize (noted as the P wave). After depolarization the last 25% of blood is ejected from the atria to the ventricles.
34
Ventricular systole
(contraction) is indicated by the QRS complex. The
ventricles depolarize then contract ejecting the blood into either the pulmonary trunk (right ventricle) or the aorta (left ventricle).
35
Approximately ________ml of blood is ejected into systemic circulation per ventricular contraction.
70ml
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Cardiac output (CO)
the amount of blood ejected from the left ventricle into the aorta per minute.
NOTE: The same is ejected from the right ventricle, during ventricular contraction.
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CO formula
= stroke volume x heart rate
ex.= 70 ml/beat x 75 beats/min
= 5250 ml/min or 5.25 L/min
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Arteries:
Thick, triple layered vessels that carry blood away from the heart.
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Arterioles:
Thin vessels formed by arteries branching down in size.
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Capillaries:
Hair-like microscopic vessels found throughout the body. Capillaries are
also known as exchange vessels, which connect arterioles to venules.
41
Venules:
Very thin vessels formed when capillaries reunite.
42
Veins:
Designated vessels that return deoxygenated blood to the heart to be
oxygenated.
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This is because veins and venules contain about
64% of the total volume of blood.
Because veins contain so much of the blood, certain veins function as blood reservoirs (liver, spleen and skin)
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Capillary filling is controlled by small arterioles and pre-capillary sphincters via
auto-regulation, (constrict or dilate), which is the ability of local tissues to blood
flow into the area according to metabolic demands.
45
Autoregulation:
The ability of local tissues to adjust blood flow (constrict or dilate) into the area according to metabolic demands via vasodilators and
vasoconstrictors.
46
Excess fluid lost is returned to the circulatory system via the
lymphatic system
47
Blood pressure
is defined as pressure exerted on the walls of the vessels as the ventricles contract.
48
Systolic BP
Highest in the aorta and the large systemic arteries.
49
volume of blood in the cardiovascular system,
normally 5 liters
or 5.3 quarts.
50
Volume or blood loss more than a____ is potentially life threatening.
10%
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Heart Rate multiplied by Stroke Volume.
Cardiac output
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Vascular resistance
is the opposition to flow (lumen size).
(a) Smaller lumen (with vasoconstriction) results in greater resistance.
(b) Greater vessel length (weight gain) results in greater resistance.
(c) Higher viscosity (as with high hematocrit) results in greater resistance.
Size
Length
Thickness
53
Blood flow to the body is regulated by the brain. The _____________, controlled by neural and hormonal feedback from 3 main types of receptors.
medulla oblongata
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3 main types of receptors of the Medulla O
(1) Proprioceptors:
(2) Baroreceptors:
(3) Chemoreceptors:
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Proprioceptors:
Monitor movements of joints and muscles.
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Baroreceptors:
Pressure receptors in the aorta and carotid arteries.
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Chemoreceptors:
Located in the arch of the aorta and carotid bodies that stimulate
sympathetic and parasympathetic response to chemical changes in the body.
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Two main circulation pathways of blood through the body:
Systemic circulation
Pulmonary circulation
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Systemic circulation:
Arteries and arterioles that carry oxygen and nutrient rich blood throughout the body, veins and venules that carry carbon dioxide and waste to the right atrium.
(a) All systemic arteries branch off the aorta.
(b) All systemic veins empty into superior vena cava, inferior vena cava, or the coronary sinus.
60
Deoxygenated blood returns to heart via the above vessels and goes into the
right atrium to be oxygenated.
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Pulmonary circulation:
Blood pumped by the right ventricle to the lungs, picks up oxygen and returns via pulmonary veins to the left atria.
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Where gas exchange takes place to re-oxygenate the blood.
Pulmonary capillaries
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Four principal branches of the aorta:
(1) The Ascending Aorta
(2) Arch of the Aorta
(3) Thoracic Descending Aorta
(4) Abdominal Descending Aorta
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Ascending Aorta
both the left and right coronary arteries branch off the ascending aorta.
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Arch of the Aorta
Brachiocephalic trunk, which then branches into:
1) Right common carotid artery: Right side of head and neck
a) External carotid: External structures of skull
b) Internal carotid: Internal structures of scull (eyeball, ear, brain)
2) Right subclavian artery:
a) Before passing into axilla, the right subclarian artery gives off a major
branch to the brain called the right vertebral artery.
(b) Left common carotid artery: Left side of head and neck
1) External carotid: external structures of skull
2) Internal carotid: Internal structures of scull (eyeball, ear, brain)
(c) Left subclavian artery: Left upper limb
(d) Subclavian arteries continue to branch further into:
1) Axillary artery: Supplies shoulder
2) Brachial artery: Supplies upper arm
3) Radial artery: Supplies lateral portion of forearm, wrist and hand
4) Ulnar artery: Supplies medial portion of forearm, wrist and hand
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(a) Bronchial arteries: Bronchi of lungs
(b) Esophageal arteries: Esophagus
(c) Posterior intercostal arteries: Intercostal and chest muscles
(d) Superior phrenic arteries: Superior and posterior surfaces of diaphragm
Thoracic Aorta
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1) Inferior phrenic arteries: Inferior surface of diaphragm
2) Common hepatic artery: Liver, stomach, duodenum, and pancreas
3) Left gastric artery: Stomach and esophagus
4) Splenic artery: Spleen, pancreas, and stomach
(b) Superior mesenteric artery: Small intestine, cecum, ascending and transverse
colons, and pancreas.
(c) Suprarenal arteries: Adrenal glands
(d) Renal arteries: Kidneys
(e) Gonadal arteries which, branches into:
1) Testicular arteries OR
2) Ovarian arteries
(f) Inferior mesenteric artery: Supplies the large intestine, part of the rectum,
descending colon.
(g) Common iliac arteries, branching to form the abdominal aorta
1) External iliac arteries: Supply lower limbs, and further branch into:
a) Femoral arteries: Lower abdominal wall, groin, external genitals, thigh
b) Popliteal arteries: Supplies muscles and skin on posterior portion of
legs, calf muscles, knee joint, femur, patella and fibula.
c) Anterior tibial arteries: Supply the knee joints, anterior muscles and
skin of the legs, and ankle joints.
d) Posterior tibial arteries: Distribute to the muscles, bones, and joints of
the leg and foot.
e) Medial and lateral plantar arteries: Supply muscles and skin of the feet
and toes.
2) Internal iliac arteries: Supplies pelvis
Abdominal Aorta
Celiac trunk which, further branches into:
68
Veins transport blood back to the heart via pressure generated by:
Contractions of the heart
The skeletal muscle pump
The respiratory pump
69
(a) The pressure generated by the contraction of heart creates a pressure difference in the circulatory system.
(b) This pressure difference helps to push the blood in one direction to empty it into the right atrium.
Contractions of the heart
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(a) Contracting skeletal muscles (especially in lower limbs) squeeze veins pushing
their contents upwards.
(b) Because of venous (one-way) valves, the blood only flows in one direction –
to the heart.
The skeletal muscle pump
71
(a) Inhalation decreases thoracic pressure and increases abdominal pressure,
enhancing blood to flow heart.
(b) Exhalation allows refilling of abdominal veins, which is then pumped to the
thoracic veins and to the heart.
(c) Pressure generated pushes blood in one direction, to the right atrium where the
pressure is approximately O mm Hg.
The respiratory pump
72
Main vein to drain the heart.
The coronary sinus
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Empties blood drained from the head, neck, chest and upper limbs into the superior portion of the right atria.
Superior vena cava
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Largest vein in the body, drains the abdomen, pelvis and lower extremities into the inferior portion of the right atria.
Inferior vena cava
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Three systematic veins carry deoxygenated blood to the heart:
Inferior vena cava
Superior vena cava
The coronary sinus
76
The three main veins that drain blood away from the head:
(1) The internal jugular- cranial bones, meninges, and brain
(2) External jugular- scalp and face
(3) Vertebral veins- cervical vertebrae, cervical spinal cord, neck muscles.
77
(a) Cephalic veins: Drains the lateral aspect of upper limb.
(b) Basilic veins: Drain medial aspect of upper limb.
(c) Median antecubital veins: Drain palms and forearms.
The principal veins that drain the upper body are the:(1) Superficial Veins
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The principal veins that drain the upper body are the:(2) Deep Veins
(a) Radial veins: Drain lateral aspect of forearm.
(b) Ulnar veins: Drain medial aspect of forearm.
(c) Brachial veins: Drain forearms, elbow joints, and arms.
(d) Axillary veins: Drain arms, axillae, and upper part of chest wall.
(e) Subclavian veins: Drain arms, neck, and thoracic wall.
79
The principal veins that drain the abdomen:
Hepatic portal circulation
(a) Blood drains from the gastrointestinal tract and spleen into hepatic portal vein.
(b) Is then delivered to the liver to be process and absorb substances from the GI
tract.
(c) Blood returns to systemic circulation through the hepatic vein.
80
The principal veins that drain the lower body are:
(1) Superficial Veins
(a) Consists of the great saphenous veins: Drain leg and thigh, groin, external
genitals, and abdominal wall.
(b) Small saphenous veins: Drain the foot and leg.
81
Deep Veins
(a) Posterior tibial veins: Drain foot and posterior leg muscles.
(b) Anterior tibial veins: Drain ankle joint, knee joint, tibiofibular joint, and
anterior leg.
(c) Popliteal veins: Drain skin and muscles and bones of the knee.
(d) Femoral veins: Drain muscles of the thigh, femurs, external genitalia, and
superficial lymph nodes.
82
How pulse and blood pressure are measured.
(1) Pulse is assessed by holding pressure on common arteries for one minute.
(2) Common arteries used:
(a) Radial artery
(b) Carotid artery
(c) Brachial artery
(d) Popliteal artery
83
Pulse rate same as heart rate, normally around 75 beats per minute (BPM).
(a) Below 60 BPM – bradycardic
(b) Above 100 BPM – tachycardic
84
Instrument used to measure blood pressure:
Sphygmomanometer, also known as
BP cuff.
85
Aging of the Heart
(1) As we age stiffening of the aorta occurs.
(2) There is a loss of cardiac muscle strength causing reduced CO and increased systolic pressure.
(a) Increasing the risk of CAD, CHF and atherosclerosis.
86
Regular exercise________________________,is essential to improve overall cardiovascular health.
at least 20 minutes 3-5 times weekly
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Examples of activities recommended:
