hsci 210 lecture midterm 2

circulatory system parts

• heart

• blood vessels

• blood

circulatory system function

• transport blood, oxygen, nutrients to the body

• help get rid of waste products

heart

blood carrying carbon dioxide

1. right atrium → tricuspid valve → right ventricle → pulmonary valve → lungs (oxygen replaces carbon dioxide)

blood carrying oxygen

1. lungs → left atrium → bicuspid valve → left ventricle → aortic valve → aorta (blood throughout body)

blood vessels

• veins: bring deoxygenated blood to heart (blue)

  • venule: intermediate between vein & capillary

• arteries: bring oxygenated blood to the body away from heart

  • arteriole: intermediate between artery & capillary

• capillaries: handoff between veins & arteries: exchange of substances between blood and tissues

  • arterial side & venous side

• vasodilation & vasoconstriction

venule

intermediate between vein & capillary

arteriole

intermediate between artery & capillary

artery

carries blood away from heart

• thickest wall

• withstand high pressure

• more (thick smooth) muscle

  • constrict & dilate

  • regulate internal temperature

• carries oxygenated blood (except pulmonary artery → lungs)

• blood travels through lumen

capillary

assists in exchange of substances between blood and tissues

oxygen & sugars allowed to pass through walls (in and out of blood)

• thinnest wall

• bigger lumen

vein

carries blood to the heart

• thinner wall

• thinner smooth muscle layer

  • less muscular and stretchy

  • low pressure

• carries deoxygenated blood (except pulmonary veins ← lungs)

• special valve: keep blood flowing only one way

pulmonary artery

carries deoxygenated blood away from heart → lungs

exception of pulmonary circuit

pulmonary vein

carries oxygenated blood toward the heart ← lungs

exception of pulmonary circuit

pulmonary circuit

arteries carry oxygenated blood away from body

• pulmonary artery: carry deoxygenated blood

veins carry deoxygenated blood to the body

• pulmonary veins: carry oxygenated blood

artery layers

1. tunica adventitia (externa): outer layer (collagen)

   1. collagen: maintain structure to keep artery open

2. tunica media (smooth muscle tissue: thick elastic muscle layer): middle layer

   1. smooth muscle (autonomic ns control): thick and elastic

3. tunica intima (endothelium) (endothelial layer) inner layer

   1. endothelial layer produce serous mucous lining for easy blood flow

4. lumen: opening

tunica adventitia (externa)

collagen: maintain structure to keep artery open

most outer layer of artery

tunica media

smooth muscle: thick and elastic

middle layer of artery

tunica intima

endothelium: endothelial cells produces serous mucous lining to ease blood flow

inner layer of artery

classification of arteries

organized by size & histology

• largest to smallest

  • elastic

  • muscular

  • arterioles

elastic artery

largest artery (1.0-2.5 cm diameter)

• closest to heart

• flexible in left ventricle, pushes out

• smooth muscle

• ex. aorta

• large tunica media layer

elastic artery histology

largest artery

• largest tunica media (smooth muscle) layer

muscular artery

medium sized artery

• peristalsis (smooth muscle): allow movement of materials through slow, wave-like contractions

• surrounded by adipose tissue

• located in digestive system & distal locations

• lots of tunica adventicia/externa

• patent: large, open lumen (structure so blood flows through)

muscular artery histology

medium-sized artery

• lots of tunica adventicia/externa

• patent: large, open lumen (structure so blood flows through)

arteriole

smallest arteries

• regulate blood pressure by restricting or dilating; changes overall resistance to blood flow (drop blood pressure to prevent capillary burst)

• mid-size betwen arteries and capillaries

• open / close capillary beds to control blood flow to certain tissues

• sphincters: open and close to manage where blood goes

• layer of endothelium surrounded by smooth muscle (thin tunica externa & tunica media)

• narrow, round lumen

• simple squamous epithelial tissue

• red blood cells in lumen

• no tunica externa

arteriole histology

smallest arteries

• layer of endothelium surrounded by smooth muscle (thin tunica externa & tunica media)

• narrow, round lumen

• simple squamous epithelial tissue

• red blood cells in lumen

• no tunica externa

artery type histology

elastic artery

• largest tunica media

muscular artery

• large tunica adventitia/externa

• large open lumen

arterioles

• endothelium surrounded by smooth muscle cells

• thin tunica externa & thin tunica media

• narrow, round lumen

• simple squamous epithelial tissue

• no tunica externa

capillary

smallest vessels

• one red blood cell, single file

• one layer of endothelium surrounded by a basement membrane

• venuole → vein → inferior vena cava/superior vena cava → heart

• endothelium sealed by tight junctions

• selectively leaky

• fenestrations: holes for passage (diffusion) of substances

  • in: nutrients, oxygen

  • out: carbon dioxide, waste

histology:

• endotholeial layer: simple squamous epithelium

• tunicas intima: lined up red blood cells

fenestration

hole for passage (diffusion) of substances

• in: nutrients, oxygen

• out: carbon dioxide, waste

capillary endothelium

simple squamous epithelium

capillary exchange

from artery oxygenated RBC: oxygen & nutrients diffuse → body cells

from body cells: carbon dioxide and waste diffuse → dexoygenated RBC

endothelial (tunica intima)

epithelial on inner lining of vessels (tunica intima)

simple squamous epithelium

• secrete and absorb

capillary endothelial: exchange blood and lymph with surrounding interstitial tissues

capillary endothelial tissue

exchange blood and lymph with surrounding interstitial tissue

capillary types

least to most vascular permeability

1. continuous: tight junctions, no seeping

2. fenestrated: holes for exchange

3. sinusoid: most permeable

continuous capillary

least permeable, most common

• tight junctions → no seeping

fenestrated capillary

middle permeability

• fenestrations (pores) for exchange

sinusoid capillary

most permeable

• wide gaps to allow exchange

capillary selective permeability

arterial end - bed for exchange - venous end

filtration (arterial end): fluid exit capillary

• high pressure inside → low pressure outside

• oxygen & nutrients EXIT

no net movement: no filtration

• equal pressure inside = equal pressure outside

reabsorption (venous end): fluid re-enters capillary

• high pressure outside → low pressure inside

• carbon dioxide & waste ENTER

inside: capillary hydrostatic

outside: blood colloidal osmotic

vein

tubes or channels carry blood from body’s capillary beds → heart

• larger opening (carries more blood)

• blood pressure declines by time blood has passed in/out of arterioles and capillaries

• vein walls much thinner than arteries

• return blood against gravity with less blood pressure

• closes to heart → widest in diameter

• simple squamous epithelium

• lumen not round

• less muscle → collapse when less blood

blood back to heart

1. pressure

2. valves: in arms & legs (some head & neck; no torso)

3. normal body movement: swinging arms & legs

4. skeletal muscle pump: muscle contraction causes blood flow (open valve, closes after push to prevent backflow)

venuole

link capillaries & veins

• most permeable region of vascular system

• no tunica media (no smooth muscle)

• tunica adventitia (externa): loose fibrous connective tissue

venuole function

• maintain blood flow

• regulate fluid exchange between vessels & surrounding interstitial tissues

• immune response (cancer, auto-immune, inflammatory, neuro-degenerative disease)

increased permeability of venuoles

inflammation

• endothelial cellls contract when triggered by histamines or bradykinan during inflammatory response

• cells contract → bigger gaps in between

• bigger gaps → allow exudate (plasma, proteins, WBCs) to leak out

blood vessels

artery

• away from heart

• more smooth muscle; high pressure

• smaller lumen

vein

• toward the heart

• less smooth muscle, more skeletal muscle; low pressure

• larger lumen

• valves

vascular pathologies

• aortic dissection

• capillary rupture

• edema (pulmonary)

• varicose veins

aortic dissection

tear in aorta inner wall → blood leak between layers of wall (separates)

weak spot (wall starts to bubble → pressure on walls → burst → aneurysm)

etiology:

• hypertension, atherosclerosis, aortic aneurysm (weakening of tunica intima), connective tissue disorders, trauma, medications (corticosteroids), family history

treatment:

• surgery & aggressive control of risk factors; surgical graft before blood burst

capillary rupture

capillary (tiny) burst → blood cells leak out under

spidery veins

treatment:

• resolves independently

edema (pitting)

interstitial tissues not draining back into capillaries & post capillary venules normally → swelling in lungs (alveoli: air sacs) due to excess fluid accumulation

similar to edema in systemic tissue

etiology:

• injury, infection, heart failure, liver/kidney disease, medication, pregnancy

treatment:

• elevation, garments, medicine, activity

varicose veins

weak venous valves → blood flow not good from increased pressure → veins swollen from blood pooling → backflow into lower extremities

etiology:

• weak valves, increased pressure, family history

treatment:

• surgical removal, techniques to close off affected veins

respiratory system function

moves air into the body and removes waste products

body cells require oxygen for respiration

• respiratory network and gas exchange in blood: oxygen breathed → body cells

• carbon dioxide exhaled → out

respiratory system structure

upper respiratory tract

• nasal cavity

• pharynx

• larynx

lower respiratory tract

• trachea

• primary bronchi

• lungs

nasal cavity & mouth

allow air to be inhaled & enter the body

nasal conchae (tubinates): warm & moisturize air

• conchae filter out dirt, pollen, particles

• adjust size to control airflow

• help with sense of smell

nasal conchae (turbinates)

warm & moisturize air

• filter dirt, pollen, particles

• adjust size to control airflow

• help with sense of smell

nasal cavity lining

vascular ciliated columnar epithelial cells lining

• mucosa: mucous secreting goblet cells

mucosa

additional nerve cells change chemical odors → chemical impulses & send through olfactory bulb (CN I) to brain

• ciliated cell: mucous transport

• goblet cell: mucous production

• connective tissue

pseudostratified columnar epithelium

mucosa epithelium

pseudostratified columnar epithelium

sinus

warm & humidify air

• hollow space produce mucous to trap stuff we don’t want in our lungs

• weight of head (skull) produce mucous to trap

oral mucosa

moist, protective lining of mouth

essential for protection, sensation, oral function

• stratified squamous epithelium

tonsils and adenoids

lymphoid tissue

plays important role in first line of defense efforts of immune systems

• tonsils removed when bacteria accumulates

larynx

voicebox controlled by muscles

tracheal cartilage allows trachea to stay open to allow air in

• epiglottis: flap closes to cover trachea

• supraglottis

• vocal cord

• glottis

• subglottis

• thyroid cartilage: adam’s apple

  • growth of cartilage draws it anteriorly to stretch & lower voices in octave

epiglottis

part of larynx

• flap closes to cover trachea

glottis

part of larynx

consist of vocal cords & openings between

• voice production; muscles open/close → sound

thyroid cartilage

part of larynx

adam’s apple

• growth of cartilage draws it anteriorly to stretch & lower voices in octave

lung location

located in thoracic cavity

• sits in pleural cavity

superior to diaphragm

flanks the heart (mediastinum)

lung surface anatomy

right lung:

• 3 lobes (superior, middle, inferior)

• horizontal fissure

• right oblique fissure

left lung:

• 2 lobes (superior, inferior)

• left oblique fissure

• cardiac notch: makes space for apex of the heart

  • left lung has leess tissue

• lingula

right lung

• 3 lobes (superior, middle, inferior)

• horizontal fissure

• right oblique fissure

left lung

• 2 lobes (superior, inferior)

• left oblique fissure

• cardiac notch: makes space for apex of the heart

  • left lung has less tissue

• lingula

cardiac notch

makes space for apex of heart (left lung)

layers of the pleura

• parietal pleura: outer

• pleural cavity with intrapleural fluid: between

• visceral pleura: inner

• diaphragm: floor

parietal pleura

outer layer of pleura

pleural cavity

filled with intrapleural fluid; siutated between parietal & visceral layers

• help lungs expand & contract smoothly

visceral pleura

inner layer of pleura

diaphragm (pleura)

floor of pleura

trachea

air passes down long tube connecting mouth + nasal cavity to rest of respiratory system

hyaline cartilage rings: sits on anterior & lateral surfaces

• not posterior: esophagus

pseudostratified (ciliated) columnar epithelium

trachea epithelium

pseudostratified (ciliated) columnar epithelium

bronchus / bronchi

trachea branches off into two bronchi (bifurcation occurs keep to manubrium)

• left main bronchus / right main bronchus

ciliated pseudostratified columnar epithelium lining

• just like oral mucosa & trachea

bronchus / bronchi epithelium

ciliated pseudostratified columnar epithelium lining

secondary bronchi / lobar bronchi

primary bronchi branch into smaller secondary tubes

bronchioles

secondary bronchi / lobar bronchi branches off into small tubes

air passes

alveolus / alveoli

bronchioles terminal branches end in microscopic balloon-like air sacs

thin epithelium for readily capillary air exchange

• site of gas exchange between air & bloodstream (oxygen inhaled, carbon dioxide exhaled)

• covered in capillaries to allow gas exchange

  • deoxygenated blood from heart → alveolus

  • oxygenated blood from alveolus → heart

• central open air sac

95% simple squamous epithelium

alveolus epithelium

simple squamous epithelium (95%)

alveolus cells

type I cells: pneumocytes

• thin, flat cells allow gas exchange between alveolus & capillaries

• from birth; cannot replicate themselves

type II cells: progenitor (stem) cells

• able to turn into more than one type of cell

• replication & differentiation into type I cells

• pneumocytes secrete surfactant to prevent collapse of alveolus & prevent innner walls from sticking together

type I pneumocytes

alveoli cells (pneumocytes)

• thin, flat cells allow gas exchange between alveolus & capillaries

• from birth; cannot replicate themselves

type II pneumocytes

alveoli cells (pneumocytes)

• progenitor cells for replication & differentiation into different cells (i.e. type I cells)

• secrete surfactant to prevent alveolus collapse & inner wall sticking

surfactant

hydrophilic lipoprotein secreted by type II alveolar cells

• maintains strucutre of alveolus upon exhale

• prevent deflating of sacs during exhalation by decreasing surface tension

• production begins 24-28 weeks; premies (<32 weeks) may have respiratory distress syndrome

diaphragm

primary breathing muscle sheet (skeletal muscle)

• facilitates inhalation & exhalation

• maintain adominal pressure → aid digestion

inhalation: contracts and moves downward (bigger thoracic cavity)

exhalation: relaxes and moves upward

ribs flexible

thoracic cavity flexibility → ribs connected to cartilage

respiration muscles

principal:

• diaphragm: increases thoracic cavity dimension, elevates lower ribs

• external intercostals: muscles in-between ribs

accessory:

• sternocleidomastoid (elevates sternum)

• scalenes (elevates upper ribs)

• pectoralis minor

accessory muscles of inspiration

extra aid for respiration; last effort to get ribs to elevate, expand, open

• sternocleidomastoid (elevates sternum)

• scalenes (elevates upper ribs)

• pectoralis minor

principal muscles of inspiration

main muscles for respitation

• external intercostals (elevates ribs)

• interchondral part of internal intercostals (elevates ribs)

• diaphragm (dome descend to increase vertical dimension of thoracic cavity (elevates ribs))

muscles of expiration

quiet breathing

• passive, elastic recoil

• lungs, rib cage, diaphragm

active breathing

• internal intercostals (pull ribs down)

• abdominalis (pull ribs down, compress abdominal contents to push diaphgram up)

• quadratus lumborum (pulls ribs down)

thoracic cage

ribs

external intercostals

muscles in between ribs (superficial)

• on external obliques

• same fiber directions: superior → inferior ; lateral → medial

• “hands in pockets”

internal intercostals

• same fiber directions: inferior → superior ; medial → lateral

breathing mechanics

air takes path of least resistance AWAY from pressure

• inspiration: high out → low in

• expiration: high in → low out

inspiration

high atmospheric pressure → low internal pressure

diaphgram contract downward

expiration

high internal pressure → low atmospheric pressure

diaphragm relax upward

sternocleidomastoid

accessory muscle elevates sternum

scalenes group

accessory muscle elevate upper ribs

quiet breathing

expiration from passive, elastic recoil

• lungs

• rib cage

• diaphragm

active breathing

• internal intercostals

• abdominals

• quadratic lumborum

regulatory mechanisms of ventilation

voluntary control

involuntary control

• higher centers of brain

• chemoreceptors (medullary, carotid body, aortic body)

• stretch receptors in lung

• proprioceptors in joints & muscles

• touch, temperature, pain stimuli receptors

val salva manuever

1. take deep breath & pinch nostrils closed → increase internal pressure

   1. increase pressure → pressure on heart and lungs → decreases cardiac output, decreases venous return, and decreases blood pressure

2. heart tells SA node to increase heart rate to compensate

   1. blood pressure initially drops in brain → hold for more than 10-20 seconds → brain blood pressure increase → hemorrhagic stroke (especially in cardiovascularly compromised)

can cause passing out

cardiac output

volume of blood the heart pumps per minute