Ex phys chapter 6 Flashcards
The Major functions of the ____ system are
- Delivers O2, nutrients
- Removes CO2, other waste
- Transports hormones, other molecules
- Temperature balance and fluid regulation
- Acid–base balance
- Immune function
Cardiovascular system
Name the 3 major circulatory system elements in the body
- Heart (the pump)
- Blood vessels (tubes and channels)
- Blood (fluid medium)
The heart Generates pressure to
drive blood through vessels
Blood flow must meet
metabolic demands
The 4 chambers of the heart are
- Right and left atria (RA, LA): top, receiving chambers
- Right and left ventricles (RV, LV): bottom, pumping chambers
the membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane is the
pericardium
The _________ is the potential space formed between the two layers of serous pericardium around the heart. Normally, it contains a small amount of serous fluid that acts to reduce surface tension and lubricate.
pericardial cavity
______is the serous fluid secreted by the serous layer of the pericardium into the pericardial cavity
Pericardial fluid
Which half of the heart carries out the following tasks:
- Pumps deoxygenated blood from body to lungs
- Superior, inferior vena cava → RA → tricuspid valve → RV → pulmonary valve → pulmonary arteries → lungs
Right Heart: pulmonary circulation
Which half of the heart carries out the following tasks?
- Pumps oxygenated blood from lungs to body
- Lungs → pulmonary veins → LA → mitral valve → LV → aortic valve → aorta
Left Heart: systemic circulation
What is cardiac muscle called?
Myocardium
_____ has most myocardium
Left Ventricle
_____ -Must pump blood to entire body
- Thickest walls (hypertrophy)
- ____ hypertrophies with exercise and with disease
- But exercise adaptations versus disease adaptations very different
left ventricle
Myocardium is only 1 type fo muscle fiber and it’s similar to type ____
1
_______ is
- High capillary density
- High number of mitochondria
- Striated
Myocardium
_________ hold cells together
desmosomes
_______ rapidly conduct action potentials
Gap junctions
________ ________ cells
- Large, long, unbranched, multinucleated
- Intermittent, voluntary contractions
- Ca2+ released from SR
Skeletal muscle
_____ cells
- Small, short, branched, one nucleus
- Continuous, involuntary rhythmic contractions
- Calcium-induced calcium release
Myocardial
Right coronary artery
- Supplies ________
- Divides into _______ & ______
- right side of heart
- marginal, posterior inter-ventricular
Left (main) coronary artery
- Supplies ________
- Divides into _____ & _______
- left side of heart
- circumflex, anterior descending
Atherosclerosis →
coronary artery disease
___ ___ is when special heart cells generate and spread electrical signal
Spontaneous rhythmicity:
The following all help carry out:
- Sinoatrial (SA) node
- Atrioventricular (AV) node
- AV bundle (bundle of His)
- Purkinje fibers
Spontaneous rhythmicity
Electrical signal spreads via
gap junctions
The Intrinsic heart rate (HR): is
100 beats/min
____ : initiates contraction signal
- Pacemaker cells in upper posterior RA wall
- Signal spreads from SA node via RA/LA to AV node
- Stimulates RA, LA contraction
SA node
_____ : delays, relays signal to ventricles
- In RA wall near center of heart
- Delay allows RA, LA to contract before RV, LV
- Relays signal to AV bundle after delay
AV node
______ : relays signal to RV, LV
- Travels along inter ventricular septum
- Divides into right and left bundle branches
- Sends signal toward apex of heart
AV bundle
_____ : send signal into RV, LV
- Terminal branches of right and left bundle branches
- Spread throughout entire ventricle wall
- Stimulate RV, LV contraction
Purkinje fibers:
when the Heart initiates its own electrical impulses:
intrinsic control
HR and force of contraction altered by extrinsic systems:
Parasympathetic nervous system
Sympathetic nervous system
Endocrine system (hormones)
Parasympathetic Nervous System Originated from the ____ and reaches heart via
brain stem
vagus nerve
vagus nerve is also known as the
(cranial nerve X)
Parasympathetic Nervous System carries impulses to the ___ & ___ nodes
SA, AV
When Parasympathetic Nervous System carries impulses to the SA & AV nodes:
- Releases ________, hyperpolarizes cells, slows spontaneous depolarization
- Decreases ___ & force of contraction
acetylcholine, Heart rate
parasympathetic nervous system decreases HR below intrinsic HR.
- Intrinsic HR: ___ beats/min
- Normal resting HR (RHR): ___ to __beats/min
- Elite endurance athlete: ___beats/min
- 100
- 60-80
- 35
the sympathetic nervous system has opposite affects of the
parasympathetic system
When the sympathetic Nervous system Carries impulses to SA, AV nodes:
- Releases ______, facilitates depolarization
- Increases __, force of contraction
- Endocrine system can have similar effect (epinephrine, norepinephrine)
- norepinephrine
- HR
when the sympathetic nervous system Increases HR above intrinsic HR:
Determines ___ during physical, emotional stress
Maximum possible HR: ___beats/min
- HR
- 250
Electrocardiogram is a recording of
hearts electrical activity
electrocardiogram is a Diagnostic tool for
coronary artery disease
What are the 3 phases of electrical activity?
- P wave: atrial depolarization
- QRS complex: ventricular depolarization
- T wave: ventricular repolarization
___ is the All mechanical and electrical events that occur during one heartbeat
Cardiac Cycle
relaxation phase of heart:
- Chambers fill with blood
- Twice as long as systolic phase
Diastole:
contraction phase:
Systole:
1/3 of cardiac cycle
Ventricular systole
Relaxation begins
- Ventricular pressure drops
- ______ valves close
- Atrioventricular valves open
- Fill 70% passively, 30% by atrial contraction
- At end, blood in ventricle = _____ _____ _____ (EDV)
- Semilunar
- end-diastolic volume
Stroke volume (SV):
volume of blood pumped in one heartbeat
Stroke volume (SV): volume of blood pumped in one heartbeat
- During _______, most (not all) blood ejected
- EDV – ESV = ___
- 100 mL – 40 mL = ___ml
- Systole
- SV
- 60 ml
Ejection fraction (EF):
percent of EDV pumped
Ejection fraction (EF): percent of EDV pumped SV / EDV = \_\_\_ 60 mL/100 mL = 0.6 = 60% Clinical index of heart contractile function
-EF
Cardiac output:
Total Volume of blood pumped per minute
(Q•) represents
cardiac output
Q• = HR x ____
RHR ~___beats/min, standing SV ~70 mL/beat
70 beats/min x 70 mL/beat = 4,900 mL/min
Use L/min (4.9 L/min)
- Stroke Volume
- 70
resting cardio output is ____ to ____ L/min
4.2-5.6
average total blood volume is
~5 L
Total blood volume circulates once every ______
minute
_____carry blood away from heart
Arteries:
______ control blood flow, feed capillaries
arterioles:
______ site of nutrient and waste exchange
Capillaries:
______ collect blood from capillaries
Venules:
_____ carry blood from venules back to heart
Veins:
___ ______ (_____)
- Highest pressure in artery (during systole)
- Top number, ~110 to 120 mmHg
Systolic pressure (SBP)
______ ______ (______)
Lowest pressure in artery (during diastole)
Bottom number, ~70 to 80 mmHg
Diastolic pressure (DBP)
______ ______ _____ (____)
Average pressure over entire cardiac cycle
MAP ≈ 2/3 DBP + 1/3 SBP –
120/80 mmHg – MAP = 93mmHG
Mean arterial pressure (MAP)
____ ____ is required by all tissues
blood flow
______: force that drives blood flow
pressure
pressure is:
-Provided by ____ contraction
-Blood flows from region of high pressure (_______) to region of low pressure (_______)
-Pressure gradient = MAP 100 mmHg in aorta – 0 mmHg in RA = 100 mmHg
Re
- heart
- LV, arteries
- veins, RA
______ force that opposes blood flow
Resistance:
easiest way to change flow is to
change vascular resistance
vascular resistance changes can be made through
- Vasoconstriction (VC)
- Vasodilation (VD)
- Diverts blood to regions most in need
_______ are resistance vessels
arterioles
Arterioles: resistance vessels
- Control systemic ______
- Site of most potent ____ &____
- Responsible for ____ to ____% of MAP drop from LV to RA across entire CVS
- resistance
- \VC and VD
- 70 to 80%
Blood flow =
ΔP/R
ΔP
- Pressure gradient that drives flow
- Change in P between LV/aorta and vena cava/RA
in the equation Blood flow = ΔP/R:
R=
Small changes in arteriole radius affect R
VC, VD
in the distribution of blood, blood flows to where:
it’s needed most
When blood flows to where it’s needed most its:
- Often, regions of ↑ _______ → ↑ blood flow
- Other examples: blood flow changes after eating, in the ____
- metabolism
- heat
at rest Q=
5L/m
When at rest kidneys receive ___% of Q and skeletal muscles receive __% of Q
- 50%
- 20%
During heavy exercise Q• =
25 L/min
Exercising muscles receive ____ % of Q• via VD
80
During heavy exercise;
Flow to liver, kidneys _____ via VC
decreases
Intrinsic Control of Blood Flow is defined as:
Ability of local tissues to constrict or dilate arterioles that serve them
The purpose of intrinsic blood flow is to
alter regional flow depending on need
the three types of intrinsic control are:
- Metabolic
- Endothelial
- Myogenic
Metabolic mechanisms (VD)
-Buildup of local metabolic by-products
– ↓ O2
– ↑ CO2, K+, H+, lactic acid
Endothelial mechanisms (mostly VD)
- Substances secreted by vascular endothelium
- Nitric oxide (NO), prostaglandins, EDHF
Myogenic mechanisms (VC, VD)
-Local pressure changes can cause VC, VD
– ↑ P → ↑ VC, ↓ P → ↑ VD
Extrinsic neural control of blood flow:
- Upstream of local, intrinsic control
- Redistribution of flow at organ, system level
Sympathetic nervous system innervates smooth muscle in arteries and arterioles
-Baseline sympathetic activity → vasomotor tone
– ↑ Sympathetic activity → ↑ __
– ↓ Sympathetic activity → ↓ __ (passive VD)
VC
At rest, veins contain ____ blood volume
2/3
At rest, veins contain 2/3 blood volume
- High _____ to hold blood -volume
- Elastic, balloon-like vessel walls
- Serve as blood ____
- capacity
- reservoir
Venous reservoir can be liberated, sent back to heart and into arteries through
- Sympathetic stimulation
- Venoconstriction
the blood volume distribution at rest:
- 13% arteries
- 7% heart
- 7% arterioles and capillaries
- 64% veins
- 9% pulmonary
Integrative Control of Blood Pressure:
Blood pressure maintained by autonomic reflexes
Baroreceptors:
- Sensitive to changes in arterial ____
- Afferent signals from baroreceptor to ____
- Efferent signals from ____ to heart, vessels
- Adjust arterial pressure back to _____
- pressure
- brain
- brain
- normal
Upright posture makes venous return to heart more
difficult
Three mechanisms assist venous return
- One-way venous valves
- Muscle pump
- Respiratory pump
3 major functions of Blood
- Transportation (O2, nutrients, waste)
- Temperature regulation
- Acid–base (pH) balance
Blood volume: _ to _ L in men, - to - L in women
- 5-6
- 4-5
Whole blood = _____ + ______
plasma + formed elements
Plasma ___ to ___% of blood volume
55-60%
plasma:
- Can _____ by 10% with -dehydration in the heat
- Can ______ by 10% with training, heat acclimation
- 90% water, 7% protein, 3% nutrients/ions/etc.
- decrease
- Increase
Formed elements
- Red blood cells (_____ 99%)
- White blood cells (_______:
- erythrocytes
- leukocytes
- Platelets
Formed elements make up ___to __% of blood
(40-45% of blood volume)
Hematocrit =
total percent of volume composed of formed elements
red blood cells without a nucleus:
cannot reproduce
Red Blood Cells:
- Replaced regularly via:_____
- Life span ~ __ months
- Produced and destroyed at equal rates
- hematopoiesis
- 4
Hemoglobin:
-Oxygen-transporting protein in red blood cells
4 O2 / hemoglobin
Hemoglobin
-Oxygen-transporting protein in red blood cells
(___ O2 / hemoglobin)
-Heme (pigment, iron, O2) + globin (protein)
-250 million hemoglobin/red blood cells
-Oxygen-carrying capacity: ___ mL O2 / 100 mL blood
- 4
- 20
Blood Viscosity:
Thickness of blood due to red blood cells
Blood viscosity:
- Thickness of blood (due to red blood cells)
- Twice as viscous as _____
- Viscosity ↑ as _______ ↑
- water
- hematocrit
- Plasma volume must ↑ as red blood cells ↑
- –Occurs in athletes after____ , acclimation
- –_______ and viscosity remain stable
- –Otherwise, blood flow or O2 transport may _____
- training
- hematocrit
- suffer