A&P II Respiratory and Urinary System

respiration

gas exchange between blood, tissue, and cells (O2 and CO2)

pulmonary ventilation

movement of air in and out of the alveoli of the lungs

alveolar respiration

gas exchange between the red blood cells in the pulmonary capillaries and alveoli in the lungs

gas transport (cells)

transport of the rbc from the pulmonary capillaries to the systemic capillaries

systemic respiration

gas exchange between the rbc in the systemic capillaries and the cells in tissues and organs

upper respiratory

functions to warm, moisten, and filter air

sinuses

nasal cavity

pharynx

lower respiratory

functions to move air and exchange gas

epiglottis

larynx

trachea

bronchi

bronchioles

alveoli

conducting zone

air is being conducted and prepared for gas exchange

TRANSPORT- nose to end of terminal bronchioles

respiratory zone

actual gas exchange with blood - respiratory bronchioles, alveolar ducts, and alveoli

Respiratory mucosa structure/ layers

mucus

epithelium (contains goblet cells which secrete mucus)

basement membrane

propina lamina (contains mucus and serous glands that also secrete mucus

mucus traps the bad stuff like dirt, pollen, and dust

(mucus has defenses against microbes like antibacterial proteins and IGA)

respiratory epithelium (structure and how it changes from nose to alveoli)

respiratory epithelium becomes thinner as you move from the nose to alveoli

pseudostratified ciliated columnar epithelium (this is the one that has those goblet cells. nasal cavity, sinuses, nasopharynx, trachea, inferior portion of the larynx, main bronchi, lobar bronchi) → simple ciliated columnar epithelium (segmental bronchi, smaller bronchi, large bronchioles) → simple ciliated cuboidal epithelium (progressive loss of cilia. terminal and respiratory bronchioles) → simple squamous epithelium (alveolar ducts and alveoli)

EXCEPTIONS: simple squamous epithelium on high abrasion areas of pharynx and on/ around the vocal cords.

what is the first conducting structure for inhaled air?

the nose

nose

one pair of lateral cartilages (hyaline)

two pairs of alar cartilages (hyaline)

nose flare part (nares) made of dense irregular CT

nasal cavity

from nostrils to choanae

where the nasal cavity meets the pharynx is called CHOANAE

the floor is formed by a palate (hard- maxilla bone, and soft- muscle)

the roof is formed by nasal, frontal, ethmoid, and sphenoid bone (plus some cartilage)

then we have a nasal septum- the anterior portion is divided by septum nasal cartilage and the posterior portion is divided by bony perpendicular plate of ethmoid plate and vomer bone.

nasal conchae

bony projections on lateral walls of nasal cavity (superior, middle, inferior)

these cause TURBULENCE which keeps pathogens out and warms the air

each passage is called nasal meatus (its name pairs up with its conchae)

regions of the nasal cavity

nasal vestibule: hairs to trap particles (just inside the nostril)

olfactory region: smell structure (olfactory epithelium)

respiratory region: pseudostratified ciliated columnar epithelium (extensive vascular network - bloody noses ☹ )

functions of the nasal cavity

warms, cleans, and humidifies

paranasal sinuses

spaces within bones lined by pseudostratified ciliated columnar epithelium

sphenoidal sinuses posterior to ethmoidal sinuses

pharynx

posterior to nasal cavity, oral cavity, and larynx

nasopharynx, oropharynx (stratifies. squamous due to food passage), laryngopharynx (stratified squamous)

lateral walls are composed of skeletal muscle

what is the larynx and what are its functions

a cylindrical airway between the trachea and laryngopharynx

functions: air passage way, prevents ingested materials like my big mac and coke zero from entering the respiratory tract, and produces sound

cartilage in the larynx

formed by 9 pieces of cartilage

epiglottis: elastic cartilage that prevents food from entering (the only thing that is elastic cartilage, everything else is hyaline)

thyroid cartilage: largest laryngeal cartilage (covers anterior and lateral walls)

• it contains the laryngeal prominence aka the adams apple

• v shaped anterior projection that has testosterone induced growth

cricoid cartilage (inferior to thyroid cartilage)

arytenoid, corniculate, cuneiform cartilage that anchors the vocal cords

laryngeal prominence

adams apple

testosterone induced growth

extrinsic muscles in the larynx to what

elevate the larynx during swallowing

intrinsic muscles of the larynx

voice production and closes off the larynx during swallowing

what two parts make up the glottis

rima glottis and vocal folds

true vocal cords

vocal ligaments made of avascular elastic CT

sound production

false vocal cords

vestibular ligaments

serve no role in sound production (no vibrate)

protect the vocal cords

sound production

intrinsic laryngeal muscles narrow the opening and air is forced past the vocal cords during respiration

carnia

splits the trachea into the two main bronchi

kind of like a median you would see on the road (CAR)

sensitive!! can make you cough if tickled hehe

trachealis and ligamentous membrane

connect the open ends of the c shaped hyaline cartilages

accommodates for the esophagus when the food bulge passes

trachealis is what contracts when we cough

what muscle contracts when we cough

trachealis muscle

histology of tracheal wall (layers of trachea)

mucus

mucosa (pseusostratified ciliated epithelium, basement membrane, lamina propina)

submucosa (areolar CT with blood vessels, nerves, lymphatic tissue, serous and mucus glands)

tracheal cartilage

adventitia (elastic CT)

bronchial tree ( and respiratory zone) work your way down

main bronchi (promary) left and right (right shorter wider more vertical)

lobar bronchi (secondary) to lobes of lungs

segmental bronchi (tertiary)

bronchioles

terminal bronchioles (end of conducting zone)

respiratory bronchioles (start of respiratory zone)

alveolar ducts (simple squamous) thin to facilitate gas exchange

alveolar sacs (simple squamous) thin to facilitate gas exchange

what happens to the wall support as bronchi divide

the wall support/ cartilage lessens

do bronchioles have cartilage?

NO. they instead have a proportionally thick layer of smooth muscle

bronchoconstriction

muscle contraction narrows bronchiole diameter

bronchodilation

muscle relaxation widens bronchiole diameter

alveoli: alveolar pores

openings that provide collateral ventilation

surrounded by pulmonary capillaries

cell types of the alveolar wall

alveolar type 1: 95%of the surface area. simple squamous. thin barrier.

alveolar type 2 (septal cells): secrete pulmonary surfactant in alveolus to oppose collapse

alveolar macrophage (dust cells): engulf microorganisms

respiratory membrane

thin barrier between alveoli and pulmonary capillaries

consists of

alveolar epithelium and basement membrane

capillary epithelium and basement membrane

break the lungs down from largest parts to smallest parts

lung are in the thorax on either side of the mediastinum. They have three surfaces

costal surface (adjacent to ribs), mediastinal surface (adjacent to mediastinum), and diaphragmatic surface (adjacent to diaphragm)

then there is a hilum which contains the root of the lung (bronchi, pulmonary vessels, nerves, lymphatic vessels)

Right lung: larger / wider. 3 lobes, 2 fissures

horizontal fissure separates superior lobe from middle lobe

oblique fissure separates middle lobe from inferior lobe

Left lung: smaller bc this is the same side the heart is. 2 lobes, 1 fissure

oblique fissure separates superior and inferior lobes

cardiac impression - medial on backside

cardiac notch on anterior surface

each lobe is organized into bronchopulmonary segments - autonomous units encapsulated by connective tissue

each segments gets their own segmental bronchus and their own pulm artery/vein, and lymph vessel

if a segment is diseased it can be removed

each segment is further organized into marble-sized lobules also encapsulated by connective tissue

each lobule gets its own terminal bronchiole, arteriole, venule, and lymph vessel

when the lungs are inflated, the pleural cavity is considered what?

a potential space bc at this point, the visceral and parietal layers are almost touching

role of serous fluid in the pleura

reduce friction and the surface tension causes the lungs to cling to the thoracic cavity wall

how do the lungs stay inflated

there are two pressures

intrapleural pressure: pressure btwn the two membranes (low)

intrapulmonary pressure: pressure in the lungs (alveolar pressure) which rises and falls but always equalizes with Patm

the intrapulmonary pressure must be greater than the intrapleural pressure to stay inflated

pneumothorax

free air in pleural cavity

this air could be introduced externally or internally (puncture)

could cause intrapleural and intrapullmonary pressures to equalize, leading to collapse

if it is a small pneumothorax, it could be resolved but larger ones are a medical emergency

boyles gas law

volume and density have an inverse relationship

autonomic nuclei in the brainstem regulate breathing activity

skeletal muscles contract/relax → changing thorax volume

these volume changes cause a change in the pressure gradient

the air moves down that pressure gradient

(work to inhale, no work to exhale)

inspiration and expiration

muscles contract → changes in volume (in the thorax) → changes in pressure → air moves down gradient

airflow depends on

pressure gradient: established between the Patm and the intrapulmonary pressure

resistance: depends on the conditions of the airway, lungs, chest wall

relationship of F= change in P/R

P and R inverse

F and change in P direct

autonomic nuclei in the brainstem coordinate skeletal muscles of breathing - nervous control of breathing (centers)

medullary respiratory center - has two groups

1- ventral respiratory group (VRG)- anterior medulla

2- dorsal respiratory group (DRG)- posterior medulla

pontine respiratory center- in the pons and also called pneumotaxic center

physiology of quiet breathing

inspiration begins when VRG neurons fire spontaneously

excite skeletal muscle for. 2 seconds

diaphragm and external intercostals contract, air flow in

quiet expiration begins when VRG is inhibited

signals from inspiratory neurons are relayed to VRG expiratory neurons

expiratory neurons send inhibitory signals back (negative feedback)

signals no longer sent to inspiratory muscles for about 3 seconds

so then diaphragm and external intercostals relax

what is the respiration rate for quiet normal breathing

12-15 breaths per minute

what is the job of pontine respiratory center

facilitates smooth transition of inhale and exhale

damage may cause erratic breathing

how does rate change (breathing)

by altering the time in inspiration and expiration

how does depth change (breathing)

changes by the stimulation of accessory muscles

chemical regulation of respiration

monitor H+, CO2, and O2 levels in ARTERIAL blood

central chemoreceptors: located in the medulla oblongata- detect changes in CSF pH (produced from blood CO2)

peripheral chemoreceptors:

arterial bodies- via vagus nerve

carotid bodies- via glossopharyngeal nerve

most important stimulus effecting breathing

PCO2. only needs to raise a little to double breathing rate

CO2 fluctuations influence sensitive central chemoreceptors

CO2 combines with water to make carbonic acid in CSF. CSF lacks protein buffers so its pH change triggers reflexes

as for PO2, this has to decrease A LOT to have any effect independent from PCO2

Altering Breathing Rate and Depth: proprioceptors

in joints and muscles

movement signals the respiratory center to increase breathing depth

Altering Breathing Rate and Depth: baroreceptors

in visceral pleura and bronchiole smooth muscle

stimulated by stretch

initiates the inhalation reflex

they also protect the lungs from overinflation

wehen overstretched, they signal the respiratory center to stop inspiration

action of higher brain centers

hypothalamus: inc breathing is body is warm

Limbic system: altering breathing rate in response to emotions

frontal lobe of cerebral cortex: voluntary control. bypass respiratory center

alveolar gas exchange

movement of gases between blood in pulmonary capillaries and alveoli

systemic gas exchange

movement of respiratory gases between blood in systemic capillaries and systemic cells

daltons law of partial pressure

total pressure: the sum of pressure exerted by each gas alone

partial pressure of a gas: the pressure exerted by that gas in a mixture

the exchange of gases in alveolar gas exchange and systemic gas exchange depend on the partial pressures

gas solubility and henrys law

at a given temperature, the solubility of a gas in liquid is dependent on

the partial pressure of the gas in the air

and the solubility coefficient of the gas in liquid

gases with lower solubility like oxygen require a higher pressure gradient to dissolve

gases with higher solubility like CO2 require less of a pressure gradient to dissolve

alveolar gas exchange: oxygen

oxygen diffuses across respiratory membrane from alveoli into the capillaries

levels in alveoli stay the same bc of the constant air exchange

continues until blood PO2 is equal to the alveoli

40 mmHg to 104 mmHg

alveolar gas exchange: carbon dioxide

carbon dioxide diffuses from capillaries to alveoli

levels higher in capillaries

continues until blood PCO2 are equal with alveoli

levels in alveoli are constant because of air exchange

systemic gas exchange: oxygen

oxygen diffuses out of systemic capillaries and into systemic cells

partial pressure gradient drives the process!!!

PO2 in systemic capillaries: 95 mmHg

PO2 in cells: 40 mmHg

continues until blood is 40 mmHg

systemic cell PO2 stays constant bc its being used at the same rate it is being delivered

systemic gas exchange: carbon dioxide

diffuses from systemic cells to the blood

partial pressure gradient drives the process

systemic cells PCO2 = 45 mmHg

capillaries PCO2 = 40 mmHg

continues until blood PCO2 is 45 mmHg

Blood’s ability to transport oxygen depends on…

the solubility coefficient of oxygen = low solubility coeff means little oxygen dissolves in plasma

the presence of hemoglobin: iron binds the oxygen. 98% of O2 in the blood is bound to hemoglobin

what are the three ways CO2 travels through the blood

1. dissolved in the plasma

2. attached to the globin of the hemoglobin

3. and as bicarbonate

what are the ways O2 travels through the blood

1. 98% attaches to the iron in hemoglobin

2. some of it dissolves in plasma (2%) it doesn’t really like to do this

do we use all of out oxygen transported?

no!

only about ¼ is released at systemic cells at rest

the left over oxygen (saturation) is called reserve and can be used in vigorous exercise

functions of the urinary system

Homeostasis: pH, BP, balancing chemicals in the body

excretion: eliminate waste, nitrogen by-products, excess ions

gluconeogenesis: during fasting

endocrine function: calcitriol, renin, erythropoietin

around the kidney deep to superficial

Fibrous capsule: dense irregular - shape and protection

Perinephric fat: adipose cushion

Renal fascia: dense irregular- anchors kidney to surrounding structures

Paranephric fat- adipose cushion

outer renal cortex

light outer segment, granular

with renal columns

inner renal medulla

contain the renal pyramids

darker

ductwork of kidneys

minor calyces → major calyces → renal pelvis → ureter → urinary bladder → urethra

what is a nephron

microscopic functional filtration unit of kidney

consists of renal tubule and renal corpuscle

the renal corpuscle and most of the renal tubule are in the cortex

renal corpuscle

glomerulus:

glomerular capillaries- tangle of capillary loops (blood leaves corpuscle through efferent arteriole and enters through afferent arteriole)

glomerular capsule- has a visceral permeable layer, parietal impermeable layer, and capsular space (receives the filtrate, which is them modified to form urine)

vascular pole (efferent and afferent arteriole) and tubular pole

renal tubule 3 parts

proximal convoluted tubule (PCT)

nephron loop

distal convoluted tubule

PCT

proximal convoluted tubule

first part of renal tubule

simple cuboidal epithelium

MICROVILLI - increases surface area and reabsorption capacity

Nephron loop

has a descending limb (extends from PCT) and an ascending limb (returns to renal cortex and connects back with DCT)

DCT

simple cuboidal but NO MICROVILLI

nephron drainage

each nephron drains into a collecting tubule

then collecting duct

then empty into papillary duct

then travel to a minor calyx

filtrate, tubular fluid, urine flow

blood flows thru glomerulus, water and solutes are filtered from blood plasma and move across the wall of glomerular capillaries into capsular space (this is filtrate!!!!)

filtrate is renamed TUBULAR FLUID when it enters the PCT. flows through PCT then nephron loop then DCT then collecting tubule then collecting duct THEN only once the fluid enters the papillary duct is it called URINE

blood supply/ flow in kidney

renal artery → segmental artery → interlobar artery → arcuate artery → interlobular artery → afferent arteriole → glomerulus →efferent arteriole → to peritubular capillaries (associated with convoluted tubules) or vasa recta (associated with nephron loop) → interlobular vein → arcuate vein → interlobar vein → renal vein

glomerular filtration: filtration membrane layers (visceral layer)

endothelium (blocks formed elements)

basement membrane (blocks large proteins)

filtration slits of visceral layer (blocks small proteins)

filtrate, three categories of substances in blood

1. freely filtered: small substances (water, glucose, amino acids, ions)

2. not filtered: large substances (formed elements, large proteins)

3. limited filtration: medium sized proteins (intermediate) but are usually blocked from filtration because of their size

net filtration pressure in corpuscle

lots of hydrostatic pressure of blood in the glomerulus bc afferent arteriole is larger so more blood coming in

some pressures oppose this like blood colloid osmotic pressure and fluid pressure in the capsular space

but hydrostatic pressure is still greater so fluid will move out

glomerular filtration rate

the rate that filtration volume is formed

it increases by increased net filtration pressure

highly regulated!! (bc this controls how much urine we make)

we can change the luminal diameter of the afferent arteriole or the surface area of the filtration membrane

renal autoregulation - intrinsic controls

myogenic mechanism (primary mechanism)

we are going to maintain a constant blood pressure despite changes in systemic bp

blood pressure increases - more stretch on wall - so it will trigger vasoconstriction

blood pressure decreases - less stretch on the wall - so it will trigger vasodilation