Anatomy and Physiology II - Chapter 15, 16, and 17/Exam 3

This goes over the Respiratory System, Digestive System, and Metabolism & Enzymes. The specific course is Anatomy and Physiology II (BIOL-2402)

respiratory system

• cellular respiration: brings in O₂, disposes of CO₂

• olfaction and speech

• physiologic buffer to maintain pH homeostasis

upper respiratory system

• nasal cavity

• oral cavity

• pharynx

• larynx

lower respiratory system

• trachea

• bronchi

• lungs

eustachian tube

connects middle ear with the nasal cavity to equalize pressure

nasal cavity

pseudostratified ciliated columnar epithelium

• goblet cells: secrete mucus to moisturize and catch smaller particles

• cilia: moves those particles away

paranasal sinuses

lighten the skull, secrete mucus that warms and moistens air

• frontal, sphenoid, ethmoid, maxillary

pharynx

skeletal muscle tube that connects the nasal cavity and mouth to the larynx and esophagus

• nasopharynx

• oropharynx

• laryngopharynx

uvula

extension of the soft palate that closes off the nasopharynx and the rest of the upper respiratory from the lower parts

larynx

attaches to the hyoid, opens into the laryngopharynx, continuous with trachea

all hyaline cartilage (minus the epiglottis)

• provides patent/open airway

• routes air and food into proper channels

• vocal folds for voice production

adam’s apple

in the larynx

a thickened piece of cartilage that is more prominent in post-puberty males

epiglottis

in the larynx, but made out of elastic cartilage and not hyaline

• covers the glottis to keep food and liquid out of the lower respiratory system

trachea

windpipe, between larynx to mediastinum

• has mucosa pseudostratified ciliar columnar epithelium and goblet cells

• outermost connective tissue encases c-shaped rings of hyaline cartilage

why are the inner hyaline cartilage rings of the trachea c-shaped?

esophagus expansion

conducting zone structural changes from the bronchi to the bronchioles

• cartilage rings → irregular plates

  • cartilage → elastic fibers

• pseudostratified columnar epithelium → cuboidal epithelium

  • less goblet cells and cilia

• smooth muscle increases for better constriction to remove harmful substances

asthma

affects the bronchioles, lack of cartilage closes them and decreases airflow

• triggers: allergies, exercise, increased eosinophils, increase of CO₂/pH drop/acidic

• usually treated with steroids

mediastinium

taken up by the heart and esophagus, in the thoracic cavity

alveoli

in alveolar sacs, 300~ million make up the majority of lung volume across 70-100 square meters

• sites of gas exchange

  • use simple squamous epithelium for passive diffusion

• surfactant cells

surfactant cells

in alveoli

secrete surfactants to make them more slippery instead of sticky

• low fluid surface tension

• allows them to stay open

lungs

take up all of the thoracic cavity minus the mediastinum

• mostly alveoli

• left lung is smaller than the right lung

apex

superior tip of the lung

deep to clavicle

base

inferior surface of the lung

rests on the diaphragm

hilus/hilum

on medial surface/part of the lung

• where pulmonary vessels, bronchi, lymphatic vessels, and nerves enter and exit

• where the bronchi and large pulmonary vessels attach

fissures

separate the lungs into lobes

left < right in terms of size

• left: separates superior and inferior lobes

• right: separates superior, middle, and inferior lobes

cardiac notch

lung concavity for the heart

visceral pleura

on the lungs’ surface

parietal pleura

thoracic cavity lining

visceral + parietal pleura relationship

high surface tension fluid → sticky → chest and lungs expand/relax together

• opposite of surfactants and alveoli, sticking together is essential

pneumothorax

trauma or excess tension → the visceral and parietal pleura separate → lung collapses

pulmonary arteries

carry deoxygenated systemic venous blood to lungs for oxygenation

feeds into pulmonary capillary networks

• blue

pulmonary veins

carry oxygenated blood from the lungs to the heart

• red

pseudostratified ciliated columnar epithelium in the respiratory system

trachea, nasal cavity, bronchi

• cleans the air

stratified squamous epithelium in the respiratory system

pharynx, mouth, esophagus

• reduces friction

simple cuboidal epithelium in the respiratory system

bronchioles

simple squamous epithelium in the respiratory system

alveoli and capillaries

• helps gas diffusion

phrenic nerve

stimulates the diaphragm

• diaphragm contracts during inhalation

• diaphragm relaxes during exhalation

  • make room for the air

boyle’s law

pressure and volume are inverse

• pressure up, volume down

• pressure down, volume up

pulmonary ventilation

exchange of gases between atmosphere and lungs

follows gradient to maintain equilibrium of pressure

• inspiration

• expiration

inspiratory muscles

diaphragm and external intercostals

• contract for inspiration

• relax for quiet expiration

accessory muscles

sternocleidomastoid and pectoralis minor

• help external intercostals during forced inspiration

abdominal muscles

internal and external obliques, rectus abdominis, internal intercostals

• contract during forced expiration

inspiration

active process that takes 2 seconds

• inspiratory muscles (diaphragm and external intercostals) contract

• lung pressure < atmospheric pressure → air flows into the lungs

  • pressure down, volume up

forced inspiration

caused by heavy exercise, COPD or a deep breath

inspiratory reserve volume (IRV)

• accessory muscles (external intercostals, sternocleidomastoid, and pectoralis minor contract)

• further volume increase in thoracic cage → more air is forced in, up to 5x

quiet expiration

passive process that takes 3 seconds

• inspiratory muscles (diaphragm and external intercostals) relax

• lung pressure > atmospheric pressure → air flows out of the lungs

  • pressure up, volume down

forced expiration

active process

expiratory reserve volume (ERV)

• abdominal muscles (internal and external obliques, rectus abdominis, internal intercostals) contract

• forces more air out

tidal volume (TV)

normal breathing, mostly from the diaphragm

vital capacity

IRV + TV + ERV

residual volume (RV)

remaining air in the lungs after forced expiration

total lung capacity/volume (TLC/TLV)

VC + RV = 6 liters usually

• 500 ml TV * 12 breaths/minute = 6000 ml → 6 liters

time for breathing

• inhale (2 seconds) + exhale (3 seconds) = breath (5 seconds)

  • 12 breaths per minute

    • (minute → 60 seconds/5 seconds for in and out = 12 breaths)

sneeze

clears upper respiratory system

cough

clears lower respiratory system

• violent coughing: liquid/food touching epithelium near carina

external respiration

passive gas exchange/diffusion between lungs (alveoli) and the blood

• oxygen: air into blood

• carbon dioxide: blood out to air

factors for the rate of external respiration

• difference in partial pressure

• surface area for exchange

• diffusional distance

• molecular weight

internal respiration

passive gas exchange/diffusion between blood and tissue

dalton’s law

partial pressure

• each gas in a mixture exerts its own pressure regardless of other gases

• all partial pressures = mixture’s total pressure

atmosphere

760 mmHG

mostly nitrogen

• 78.6% nitrogen

• 20.9% oxygen

• 0.04% carbon dioxide

• 0.06% other gases

• 0.40% water vapor

henry’s law

solubility of gases in a solution

• amount of gases that will dissolve in a solution (plasma) at a constant temperature depends on

  • partial pressure

  • solubility

solubility

how well does the gas go into the solution

most soluble to least soluble:

• carbon dioxide: super soluble (24x)

• oxygen: partly soluble in water (plasma)

• nitrogen: barely soluble and doesn’t really affect our body

RBCs/hemoglobin in oxygen transport

hemoglobin helps blood’s oxygen carrying capacity by 98.5%

• each molecule carries 4 O₂ molecules

fully saturated (hemoglobin and partial pressure of oxygen)

all hemoglobin oxygen binding sites are filled

• aorta (100% saturation)

partially saturated (hemoglobin and partial pressure of oxygen)

blood carries mix of saturated and deoxygenated hemoglobin

• decreases from the aorta, but still has some oxygen

circulation of P_O2

• aorta (100% saturation) →

• systemic arteries (100 P_O2 > 40 P_CO2 → release O₂, absorb CO₂)

• muscles → (STEEP INCREASE)

• peripheral tissues →

• systemic capillary (about P_O2 = P_CO2) →

• systemic veins

affinity

how tightly does hemoglobin bind to O₂

when should blood hemoglobin release O₂/low affinity?

high affinity

easier, hemoglobin is saturated at low PO2

• retains O2

low affinity

harder, hemoglobin needs high P_O2 to become saturated

• releases O₂

factors for affinity

• pH

• CO₂

• temperature

• CO

• fetal hemoglobin

pH of blood

7.40, slightly alkaline

• 7.35-7.45

pH (affinity)

direct

aids in O₂ delivery to tissues and O₂ pick up from lungs

• low pH/acidic: low affinity

• high pH/basic/alkaline: high affinity

CO₂ (affinity)

inverse, linked to pH

aids in O₂ delivery to tissues

• P_CO2 up → affinity down

• P_CO2 down → affinity up

bicarbonate reaction

why pH and CO₂ are linked/inverse

CO₂ + H₂O ←[carbonic anhydrase]→ H₂CO₃ ←[dissociates]→ H⁺ + HCO₃^-

carbon dioxide + water ←[carbonic anhydrase]→ carbonic acid ←[dissociates]→ hydrogen ion + bicarbonate ion

• CO₂ up → pH down/acidic

• CO₂ down→ pH up/alkaline/basic

temperature (affinity)

inverse, linked with exercise

• temp up → affinity down

• temp down → affinity up

CO (affinity)

carbon monoxide

• has a high affinity for iron in hemoglobin → O₂ transport down

fetal hemoglobin (affinity)

higher affinity for O₂ than maternal

• ensures fetus’ O₂ if mom has low levels

CO₂ transport in blood

24x more soluble in plasma, takes 3 forms in blood

MOSTLY AS BICARBONATE IONS!!!

• dissolved CO₂: 7%, in plasma

• in RBC

  • bicarbonate ion: 70%

  • carbaminohemoglobin: 23%

carbaminohemoglobin

HbCO₂, 23% of CO₂ in blood

binds to globin

• NOT iron/heme

CO₂ circulation in bloodstream

CO₂ diffuses

• 7% remains as dissolved CO₂

• 93% goes into RBC

  • 23% binds to hemoglobin as carbaminohemoglobin

  • 70% is bicarbonate ions that go through the bicarbonate reaction

    • H+ binds to hemoglobin = HbH⁺

    • HCO₃^- exchanges with chloride ion (Cl^-) into plasma

respiration control

by respiratory center (higher brain centers’ neurons in the medulla and pons), chemoreceptors, and other reflexes

medullary rhythmicity area (respiratory center)

in medulla, controls basic breathing patterns (12 breaths/min)

• inspiratory neurons: normal breathing

• expiratory neurons: active during forceful exhalation

pneumotaxic area (respiratory center)

in pons, impulses shorten inhalation and promote exhalation

• activity up → breathing rate/speed up

apneustic area (respiratory center)

in pons, activates and prolongs inhalation and inhibit exhalation

• occurs while pneumotaxic area is inactive to slow breathing (activity up → breathing rate/speed down)

regulation of respiratory centers

by cerebral cortex, limbic system, hypothalamus

cerebral cortex (regulation of respiratory centers)

allows conscious control of breathing and the ability to not breathe

• depends on CO₂ and H⁺ buildup in blood, too much causes inspiration regardless

  • CO₂ or H⁺ up → stimulates inspiration → breathing resumes regardless

central chemoreceptors (regulation of respiratory centers)

in medulla

senses pH changes

• pH down/acidic/H⁺ stimulates → synapses with respiratory regulatory centers → breathing depth/rate up → P_CO2 down → pH up/basic/alkaline

peripheral chemoreceptors (regulation of respiratory centers)

in aorta and carotid arteries

senses O₂ changes

• low O₂ stimulates → ventilation up

proprioreceptors (regulation of respiratory centers)

reflex: movement/exercise up → breathing up

• can also happen passively with immobile patients

exercise (regulation of respiratory centers)

depends on intensity and duration

• P_CO2, P_O2, and pH are constant

• metabolic needs → hyperpnea/increased ventilation (10-20x)

hering-breuer reflex (regulation of respiratory centers)

prevents overstretching lungs

• inhalation reflex: lung baroreceptors prevent overfilling

• exhalation reflex: stimulates exhalation

P_O2 (regulation of respiratory centers)

peripheral chemoreceptors in aorta and carotid arteries

• low O₂ stimulates → ventilation up

  • not much of an effect on ventilation due to hemoglobin’s O₂ reserve

P_CO2 (regulation of respiratory centers)

hypercapnia/blood P_CO up → CO₂ buildup in brain → bicarbonate reaction → pH down/acidic →

• H⁺ stimulates central chemoreceptors in medulla

  • slow, shallow breaths → CO₂ up → pH down/acidic

  • fast, deep breaths → CO₂ down → pH up/basic/alkaline

hyperventilation effect on CO₂

CO₂ down → pH up/basic/alkaline →

respiratory alkalosis

asthma and pneumonia effect on CO₂

CO₂ up → pH down/acidic →

respiratory acidosis

COPD effect on CO₂

CO₂ is always elevated, can’t trust

rely on O₂ sensors

• if given O₂ → respiratory centers stop

what can cause breathing rate to increase?

basically, when would you want more oxygen to be released?

• CO₂ up

• H⁺ up/pH down/acidic

• O₂ down

• temp up

• proprioceptor movement up

• SNS stimulation (fight or flight, adrenaline, adrenergic fibers)

pulmonary irritant reflexes

bronchiole receptors sense irritants → vagal nerve afferents → respiratory centers → reflexive air passage constriction up

• same irritant → cough in trachea/bronchi; sneeze in nasal cavity

smoking

very addictive, decreases anxiety

• tar in lungs → cilia falls off trachea/windpipe → mucus up → coughing

• CO inhalation → O₂ down

• risk increases for: cancer, heart attack, type 2 diabetes, gum disease, teeth loss, blood clotting, emphysema, respiratory infections

pneumonia

secondary infection

gas exchange down, which can be fatal

• at risk: COPD, elderly, compromised, stressed

developmental aspects of respiration

• 25th week baby can breath by itself

• fetal life: lung is filled with fluid and blood bypasses the lungs

  • gas exchange occurs with the placenta

respiratory distress syndrome

premature babies have nonfunctioning surfactant-secreting cells → low surfactant levels → very sticky, hard to breathe

pulmonary embolism

usually starts in leg veins, usually diagnosed on autopsy

• factors: surgery, inactivity, dehydration, pregnancy, birth control, excess blood clotting

• symptoms: shortness of breath, fatigue, leg pain

• prevention: low dose heparin

sleep apnea

uvula (extension of soft palate) blocks glottis (airway opening) during sleep → blocked airway