Ex Phys Quiz 1

arteries

- thicker tunica media

- built to handle high pressure

veins

- thinner walls

- more compliant (act as blood reservoirs)

endothelium

- controls vessel size

- regulates vascular tone

hypetension

causes endothelial stress and dysfunction

tunica media

- composed of smooth muscle

- controls vessel diameter

- regulates: vascular resistance & blood flow

- especially important during exercise

stroke volume

blood ejected per beat

sympathetic stimulation (heart)

- ↑ myocyte contraction force

- ↑ stroke volume

- ↑ cardiac output

preload (Starling's Law)

amount of blood in the heart chamber before contraction

left ventricular end-diastolic pressure

- describes preload

- pressure at the end of diastole

increased venous return --> increased preload

true

1 multiple choice option

decreased venous return

- ↓ LVEDP

- Poor actin-myosin overlap

- ↓ stroke volume

afterload

resistance the heart must overcome to eject blood

systole

ventricular contraction

diastole

ventricular relaxation

LUB

AV valves close

DUB

semilunar valves close

muscle pump

- skeletal muscle contraction compresses veins

- increases transmural pressure

- prevents blood stagnation

respiratory pump

- Inhalation ↓ thoracic pressure

- Helps venous return to the heart

- Faster breathing → increased heart rate

sympathetic vasoconstriction

- smooth muscle contraction stiffens veins

- pushes blood back to the heart

peripheral vascular disease

- Varicose veins

- Blood stagnation in venous system

- ↑ risk for DVT

low preload

- Poor filament alignment

- ↓ tension

- ↓ stroke volume

mitral valve regurgitation

- Blood flows back into atrium during systole

- Stroke volume may be high but effective CO decreases 

- ↓  LVEDP

- Pulmonary edema → SOB

aortic valve stenosis

- Narrow valve → harder to eject blood

- ↑ afterload

- ↓ stroke volume

hypertension

- ↑ afterload

- Harder to pump blood out

- ↓ stroke volume

stroke volume resistance depends on

- blood viscosity

- vascular tone

baroreceptor relfex

a reflexive change in cardiac activity in response to changes in blood pressure

aortic arch receptor

transmits via vagus nerve to medulla, responds only to an increase in BP

increased vagal tone to SA node

- decreases HR

- decreases CO

decreased sympathetic tone to vessels

- vasodilation

- decreased resistance

bainbridge reflex

- aka atrial reflex

- atria stretches due to increased venous system

chemoreceptor reflex is triggered by

- hypoxia

- hypercapnia

- acidosis

pulse pressure equation

SBP - DBP

MAP equaltion

DBP + 1/3 (SBP-DBP)

dynamic exercise (contract & relax)

- ↑ venous return

- ↑ preload

- ↓ peripheral resistance

- ↓ afterload

static exercise (contract & hold)

- Sustained muscle contraction

- Muscles compress blood vessels

- ↑ blood pressure

- ↑ peripheral resistance

- Very high afterload 

VO2 max

the maximum amount of oxygen the body can take in and use during exercise

sympathetic stimulation or HR

- ↑ ion leak 

- Reach threshold faster

- ↑ HR

parasympathetic stimulation for HR

- ↓ ion leak

- Reach threshold slower

- ↓ HR

what two NTs bind to B1 receptors?

- epinephrine

- norepinephrine

epinephrine & norepinephrine bind to B1 receptors which leads to

- increase rate of depolarization

- increase HR

beta blockers

- Block B1 receptors

- Prevent epinephrine & norepinephrine binding

- ↓ HR

- ↓ cardiac output

- ↓ blood pressure

dynamic exercise

- ↓ peripheral resistance

- ↓ afterload

- ↑ venous return

- ↑ preload

- Heart works with more volume

static exercise

- ↑ peripheral resistance

- ↑ afterload

- Heart works with more pressure

dynamic exercise BP

- Systolic BP ↑

↑ venous return 

↑ contractility 

↑ stroke volume 

- Diastolic BP ↓

↓ peripheral resistance

static exercise BP

- Very large rise in systolic BP

- Caused by vessel compression

- ↑ afterload

- Heart must pump against high resistance

Ischemia

- Imbalance between oxygen demand and supply

- Insufficient blood flow → insufficient oxygen

- Tissue shifts to anaerobic metabolism

- Can occur due to:

↑ demand not met

↓ supply not met

infarction

- prolonged ischemia

- tissue death due to lack of oxygen

hypertrophic cardiomyopathy

- enlarged heart

- less efficient pumping

- increased risk of heart failure

- due to chronic exposure to high afterload

P wave

atrial depolarization

QRS complxe

- ventricular depolarization

- atrial repolarization

- large peak due to large ventricular muscle mass

T wave

ventricular repolarization

what happens during exercise?

- increase in command (efferent) signal from motor cortex

- increase in sympathetic activity via neural stimulation and circulating catecholamines

- increased afferent signal from muscle/tendon ergoreceptors

- increased afferent signal from muscle metabolic receptors

oxygen lack theory

tissue metabolism increases --> local O2 levels decline --> insufficient O2 for smooth muscle sphincters to maintain contractino --> sphincter looses tone, blood flow increases --> oxygen arrives, smooth muscle regians ability to contract, blood flow reduced

vasodilator theory

increased metabolism/insufficient O2 delivery --> accumulation of by-products of metabolism in interstitial space --> vasodilation via action on pre-capillary sphincters and arterioles

absolute contraindications to execise testing

- acute coronary syndrome

- arrhythmias

- valvular disease

- inflammatory heart condition

- vascular issues

- heart failure

- respiratory distress

fick equation

VO2 = Q x a-vO2 difference

if you exercise less than 3 times a week...

- there will be little to no change in VO2

- possible functional improvement only

general recommendation for frequency of exercise

3-5 days per week

frequent exercise leads to

- ↑ stroke volume

- ↓  resting heart rate

- ↓  submaximal heart rate

- ↑ endothelial function 

- ↑ vascular compliance 

low intensity

walking slowly

moderate intensity

brisk walking (can talk, but not sing)

vigorous intensity

running (must pause for breath during conversation)

how to measure intensity

- heart rate

- RPE

Physiological Effects of Increasing Intensity

- ↑ heart rate

- ↑ stroke volume (up to moderate intensities;; plateaus at higher levels in most individuals)

- ↑ cardiac output

- ↑ a-vO2 difference

- ↑ sympathetic activation

excessive intensity can cause

- Exaggerated blood pressure response

- Large rise in systolic BP

- Possible abnormal diastolic BP response

recommendation for duration of exercise

- 20-60 minutes per day

- can be continuous or intermittent

- minimum or 10-minute bouts

lower intensity --> duration?

longer duration required (30-60 min)

higher intensity --> duration?

shorter duration sufficient

Physiological effects of time

- Sustains cardiovascular demand

- Influences plasma volume shifts

- Affects thermoregulation

cardiovascular drift

- occurs during prolonged exercise (> 10-15 minutes)

- ↑ HR

- ↓ stroke volume

- caused by: increase skin blood flow & plasma volume depletion (sweating)

excessive HR rise may indicate

- increased sympathetic drive

- low fitness level

systolic blood pressure (SBP) during exercise

- Increases with intensity

~ 10 mmHG per MET

- Due to: ↑ Cardiac output, ↑ contractility, & ↑ stroke volume

diastolic blood pressure (DBP) during exercise

- Remains stable or slightly decreases during dynamic exercise 

- Due to: ↓ peripheral resistance & ↓ afterload 

- Vasodilation in active muscles 

red flags to stop exercise

- SBP fails to rise or drops with increase workload

- Excessive SBP rise (>250 mmHg)

- Exercise should be stopped approaching ~200 mmHg, depending on clinical context

- DBP increase > 10 mmHg during exercise

- Suggest excessive afterload

- Delayed HR recovery post-exercise

conducting zone (anatomical deadspace)

trachea --> primary bronchi (left & right) --> secondary (lobar) bronchi (2 left & 3 right) --> tertiary (segmental) bronchi (10 right, 8 left) --> interlobular bronchioles (<1 mm) --> terminal bronchioles (< 0.5 mm)

respiratory zone (ascini)

respiratory bronchioles (0.5 mm diameter) --> alveolar ducts (lined with alveoli) --> alveolar sacs --> alveoli

conducting zone

- has NO gas exchange

- NOT designed for gas exchange

- first 150 mL you breathe in does NOT get your alveoli for gas exchange

respiratory zone

- gas exchange takes place

- O2 in bloodstream

- CO2 out bloodstream

cartilage rings

- NO gas exchange can happen

- horseshoe shape allows esophagus to expand

what structures have cartilage rings?

- primary bronchi

- secondary (lobar) bronchi

- tertiary (segmental) bronchi

what structure has smooth muscle & elastic tissue?

- interlobular bronchioles (<1 mm)

- terminal bronchioles (<0.5mm)

- respiratory bronchioles

what structure epithelial cells?

- thin & have a massive surface area

- alveolar ducts

- alveolar sacs

- alveoli

the conducting zone has higher resistance because

the cross-sectional area is small

the respiratory zone has lower resistance because

the cross-sectional area is large

autonomic reflexes within the airway

- sympathetic drive

- parasympathetic drive

- irritant reflex

- low PCO2

sympathetic drive

- B2-adrenergic receptors cause relaxation of airway smooth muscle - bronchodilation

- Albuterol

parasympathetic drive

- Acetylcholine receptors cause contraction of airway smooth muscle - bronchoconstriction

- Ipratropium

irritant reflex

Particularly excite airway receptors and induce a bronchoconstriction

low PCO2

direct action on airway smooth muscle

inspiratory muscles

- diaphragm

- external intercostals

- SCM (Accessory Muscles)

- scalenes (Accessory Muscles)

- pectoralis minor (Accessory Muscles)

anterior portion of the diaphragm originates at the

ribs

3 multiple choice options

posterior portion of the diaphragm originates at the

vertebrae

3 multiple choice options

external intercostals

contract and pull the ribs up and outward

expiration is usually passive due to the recoil of the lungs

true

1 multiple choice option

expiratory muscles

- rectus abdominis

- external oblique

- internal oblique

- increase abdominal pressure

visceral pleura

lines the lung

parietal pleura

lines the thoracic cavity

intra-pleural space

fluid-filled space between the parietal and visceral pleura

what two things generate negative pressure in the pleural space?

- recoil of the lung

- spring of the chest wall

inspiration does what to pleural pressure

- Volume ↑ 

- Intrapleural pressure gets more negative 

- Flow & alveolar pressure goes from 0 to more negative