BIOL 320 LAB PRACTICAL 2

Two main groups of the digestive system

alimentary canal

accessory digestive organs

Alimentary canal

AKA gastrointestinal (GI) tract

one, long, muscular, hollow tube that extends from the mouth to the anus

includes the mouth, pharynx, esophagus, stomach, and small/large intestines

along this path, food can be broken down into smaller pieces that can be absorbed through the lining

Accessory digestive organs

teeth, tongue, gallbladder, salivary glands, liver, and pancreas

Five main processes of digestion

ingestion

propulsion

mechanical and enzymatic digestion

absorption

elimination

Mechanical and enzymatic digestion begin in the...

mouth

salivary glands produce the carbohydrate metabolizing enzyme amylase in addition to saliva to aid in digestion of food particles

Sections of the small intestine

duodenum

jejunum

ileum

Liver produces...

bile

What does bile do?

helps move lipid particles through the small intestine

Most lipid digestion takes place in the...

small intestine

Lipase is produced in the...

pancreas

The liver converts...

fructose and galactose into glucose

Enzymes are _________ in the stomach

inactivated

What type of acid is in the stomach?

hydrochloric acid (HCl)

The Arcade

the extensive anastomosis network in the vessels of the gut

Muscle(s) of tidal inspiration

External intercostals

diaphragm

Muscle(s) for forced inspiration

Sternocleidomastoid

Muscle(s) of tidal expiration

Diaphragm relaxes

Pulmonary surfactant

surface-active lipoprotein complex (phospholipoprotein) formed by type II alveolar cells

acts to reduce surface tension and reduce fluid accumulation - keeps airways dry

Insufficient surfactant

collapsed alveolus

inadequate oxygen exchange

Sufficient surfactant

expanded alveolus

adequate oxygen exchange

Common iliac vein is...

unique to humans

Primary function of the respiratory system

release CO2 from the body and acquire O2 for use by the body

Respiration can be thought of as four steps:

Pulmonary ventilation

External respiration

Transport of respiratory gasses

Internal Respiration

Pulmonary Ventilation

movement of air in and out of the lungs so that the gasses in the lungs are constantly refreshed with infusions of new air and effusions of old air

External Respiration

Carbon dioxide diffuses to the lungs from the blood, and oxygen diffuses to the blood from the lungs

Transport of Respiratory Gasses

CO2 is transported from the cells of body tissues to the lungs, and O2 is transported from the lungs to the cells of body tissues

Internal Respiration

O2 diffuses from the blood to the cells of the body, and CO2 diffuses from the cells of the body to the blood

Upper Respiratory System

consists of the structures from the nose to the larynx

Lower Respiratory System

consists of the larynx and the structures inferior to it

Function of the Nose

warms and moistens the air

provides a resonating chamber for vocalizations

cleans and filters entering air

houses the olfactory receptors

What causes the difference in nose shapes?

Differences in nasal cartilages

Nose bones are pretty consistent

Superior nasal cavity is lined with...

Olfactory mucosa

Olfactory mucosa

Contains smell receptors

Rest of the nasal cavity is lined with...

pseudostratified ciliated columnar epithelium

Pseudostratified Ciliated Columnar Epithelium contains...

contains goblet cells and seromucous glands

Seromucous glands have:

cells that secrete mucus to trap bacteria and debris

cells that secrete a watery, enzyme rich fluid to humidify and kill bacteria (lysozyme)

Respiratory mucosa epithelial cells secrete...

antibiotic defensins to assist in killing microbial invaders

Cilia of the nasal cavity

sweep contaminated mucus towards the throat to be swallowed and digested

How does cold air effect nasal cilia?

Slows the cilia and thus allows some mucus to dribble out the nostrils

Sneeze Reflex

when irritants contact the rich supply of sensory nerve endings in the nasal cavity

sneezing forced the irritants out to protect the body from them

Veins and plexuses of capillaries near the nose

Function to warm air as it is inspired

Cold air reflexively stimulated these plexuses to engorge with blood allowing for greater heat transfer

Nose bleeds

the superficial location of capillaries and plexuses of the nose exposes and makes them easy to damage, resulting in nose bleeds

Nasal conche

increases surface area and helps create turbulence, which deflects non-gaseous particles onto the mucus coatings

Heat moisture gradient

constantly flipping each time we breathe out and then back in

Paranasal sinuses

Lighten the skull

Prone to inflammation due to infection or allergies

4 Paranasal Sinuses

frontal, sphenoid, ethmoid, maxillary

Sinusitis

inflammation of the sinuses

What happens when the sinuses are inflamed?

Additional mucus is produced and can block the openings between the sinus and the nasal cavity

The air in the sinus is absorbed and a partial vacuum is created, which causes the pain with a sinus headache

Inflammation of the nasal mucosa

can cause excessive mucus production leading to congestion and postnasal drip

What structures move superiorly during swallowing?

The SOFT PALATE and the UVULA move superiorly to block off the NASOPHARYNX

What moves over the larynx during swallowing?

The EPIGLOTTIS moves over the larynx to keep food out of the nasal cavity and lungs

Within the nasopharynx, what propels mucus towards the stomach?

Cilia!

Pharyngeal tonsil

Adenoid

contains lymphatic tissue that traps and destroys pathogens

When the pharyngeal tonsils are swollen,

they can block air passage and force the patient to breath through the mouth which greatly decreases the warming, filtering, and humidifying effects on the air

Pharyngotympanic tubes

connect the middle ear to the nasopharynx so that the air in the middle ear can match pressure with the atmospheric air

this is important for sound conduction and proper hearing

Oropharynx and laryngopharynx

receive both food and air and thus have a more protective stratified squamous epithelium

Respiratory zone

site of external respiration (gas exchange)

made up of the alveoli, alveolar ducts, and respiratory bronchioles

Conducting zone

consists of all the tubes transporting air from the nose to the respiratory bronchioles

air is humidified, filtered/cleansed, and warmed in the conducting zone

Where are the vocal chords/fold housed?

Larynx

Adams Apple

laryngeal prominence of the thyroid cartilage

Why is the Adams Apple more prominent in males?

Because the thyroid cartilage is stimulated by androgens during male puberty to grow larger

estrogens stimulate fat deposition in the necks of women, which obscures their smaller laryngeal prominence

Arytenoid cartilages

anchor the vocal folds

When we are conscious, anything other than air entering the larynx ...

will generate a cough reflex

this is why liquids should never be given to an unconscious patient

Glottis

the vocal folds and the opening between them

Below the vocal folds, into the larynx and trachea, the epithelium changes back to...

pseudostratified ciliated columnar epithelium

BUT the cilia here sweep the mucus upwards towards the pharynx to be swallowed

What does the glottis do during speech?

Opens and closes during intermittent expiration to produce speech

What muscles move the cartilages of the larynx?

laryngeal muscles

What do the laryngeal muscles aid in?

they change the length of the vocal folds and size of the glottis to change pitch and produce vocalization

How does male puberty effect the voice?

when the thyroid cartilage is enlarging, the rest of the larynx and the focal folds (become longer and thicker) enlarge to produce a deeper voice

How is loudness determined?

by the force with which the air is expired across the vocal folds

How do the pharynx, nasal, oral, and sinus cavities effect loudness?

they resonate the sounds to enhance and amplify them

What muscles are used for enunciation?

muscles in the lips, soft palate, tongue, and pharynx

Laryngitis

inflammation of the vocal folds causing them to swell and vibrate incorrectly

results in horse tone and is caused by viral infection

Valsava maneuver

-vocal folds can completely closer over the glottis to stop air passage, such as when straining to defecate

-abdominal muscles contract and the glottis closes to increase intra/abdominal pressure to help empty the rectum

-increases the pressure of the thorax which decreases venous return to the heart by squeezing on major blood vessels

-presses on the Vagus nerve to increase vagal tone, which also slows HR

Volume changes cause...

pressure changes, which cause gases to flow down pressure gradients

Boyle's Law

At a constant temp, the pressure of a gas varies inversely with its volume

A gas will always...

fill the volume of the container they are in

Expiration is largely...

passive

the recoil of the diaphragm up into the thorax

relaxed external intercostals allow the ribs and sternum to depress

Forced deep expiration

contracting the abdominal wall muscles. which pushes the organs superiorly against the thorax

rig cage is pulled inferiorly to further increase pressure in the thorax

Singers have a good ability for...

forced expiration

very similar to the valsava maneuver in that it decreases HR

Inspiration

we release tension on the thorax and increase the volume by contracting the diaphragm and external intercostals to raise the ribs and sternum

this decreases pressure in the thorax until it is lower than the atmospheric pressure, which allows air to flow in and down the pressure gradient

Deep inspiration

Several additional muscles are recruited (pectorals minor and scalenes)

This releases pressure on great vessels, allowing a larger venous return, thus increasing heart rate

HR ___ when we expire, and HR ___ when we inspire

HR decreases when we expire, and HR increases when we inspire

Layers of the trachea

mucosa

submucosa

adventitia

Elastic V Inelastic parts of the trachea

Elastic part of the trachea allows it to move during breathing

The inelastic cartilage hold the trachea open so that air can continuously move

Trachealis muscle

lies between the esophagus and trachea

allows for rapid mvmt of air and mucus out of the lungs and trachea during coughing

Passageways in the lungs where branching produces diameters smaller than 1 mm are termed...

bronchioles

Cartilage distribution in the respiratory system

cartilage rings are present in the upper bronchial tree

they turn into cartilage patches

there is no cartilage in bronchioles

How does the epithelium change within the bronchial tree

as the conducting tubes become smaller, the mucosal epithelium thins until ultimately becoming cuboidal in the terminal bronchioles and containing few cilia & mucous containing cells

How does muscle change within the bronchial tree?

as tubes decrease in diameter, the percentage composition of smooth muscle increases

this allows for constriction and dilation to control the resistance to air passage to control physiological demands (ex: dilation during exercise)

Alveolar sac

cluster of alveoli coming off an alveolar duct

Alveoli

single thin layer of squamous epithelial cells make up the alveolar walls

densely covered with pulmonary capillaries

Respiratory membrane

capillary and alveolar walls with their fused basement membranes

where gas exchange occurs

Ventilation-perfusion coupling

blood that is low in O2 and high in CO2 is always washing onto the alveoli

air that is high in O2 and low in CO2 is constantly being refreshed into the alveoli

Ventilation

amount of gas reaching the alveoli

Perfusion

blood flow in the pulmonary capillaries

Type II alveolar cells

secrete antimicrobial proteins and SURFACTANT

How are alveoli connected to each other?

Alveolar pores

provide alternate pathways for air to get to alveoli that might be blocked

pores allow for equalization of air pressure throughout the entire lung

The lungs take up the thoracic cavity except for the ...

mediastinum

houses the heart, great vessels, esophagus, bronchi, and other organs

What directly surrounds the lungs?

the PLEURA!

parietal (more superficial) and visceral (directly on lungs) layers