Mouth, Teeth, Pharynx

Stomodeum

The embryonic precursor to the mouth, forming from the anterior end of the developing digestive tract. It is significant in the early stages of development.

Where does the pharynx form

posterior to the pharynx

what germ line lines the oral cavity

By the ectoderm, which gives rise to epithelial structures in the mouth.

where does the gut tube start

the pharynx

What does the pharynx perform

respiratory and digestive system functions by facilitating the passage of air and food.

In early vertebrates the pharynx is the major respiratory structure but in humans

the lung is, because we do not have gills

In fish what are the 2 chambers of the heart

1. atreum

2. ventricle

Atrium

low pressure large collecting place (blood collecting)

ventricle

pumping chamber of the heart that receives blood from the atrium and pumps it to the ventral aorta.

deoxygenated blood from the aorta splits towards where

the gills

afferent branchial arteries

arteries that carry deoxygenated blood from the gills back to the heart.

efferent branchial arteries

arteries that carry oxygenated blood from the gills to the aorta.

in mammals what does the pharynx do

serves as a separation between respiratory and digestive tracts

what always takes priority

the food

what does the ventral tube carry

air

what does the dorsal tube carry

food

epiglotis

in the presents of food and water it snaps down so they don’t go down the trachea

The uvula

blocks food from the nasal cavity, which helps when a mammal is nursing

7 openings to the pharynx

1. oral cavity

2. & 3 paired internal nares

4. esophagus

5. trachea

6. & 7 paired eustachian tubes

3 pharynx regions

1. nasopharynx

2. oropharynx

3. laryngopharynx

nasopharynx

superior behind the palate and to the choanae

oropharynx

directly behind the mouth

laryngopharynx

behind larynx below the epiglottis

Eustachian tubes

small tubes that connect the middle ear to the nasopharynx, helping to equalize ear pressure.

larynx

passage between the laryngopharynx and trachea

What does the larynx do

• separates food/water + air

• Regulate breathing

• vocalization

cricoid cartilage

The cricoid cartilage is a ring-shaped structure located below the thyroid cartilage in the larynx, providing support and preventing airway collapse.

tongue

modified hypobranchial muscle anchored by hyoid apparatus

tongue function

• food handling

• taste buds

• move scent to vomeronasal organ

• prey capture

• grooming

• speech

vomeronasal organ

imbedded on the roof of the mouth extending from nasal cavity that detects pheromones and chemicals.

polyphydont

multiple generations of tooth replacements (most vertebrates)

Diphydont

two sets of teeth: milk and permanent (most mammals; incisor, canine and premolar teeth are replaced)

monophydont

a single set of teeth (e.g., cetaceans)

homodont

teeth of similar shape along the jaw

heterodont

teeth of different shape along the jaw

Heterodonty is

a synapomorphy for mammals that have produced 4 tooth types

4 types of teeth

1. incisors

2. canine

3. premolar

4. molar (typically not replaced)

aradicular hypsodont teeth

are teeth that continue to grow throughout an animal's life, commonly seen in some herbivores, allowing them to wear down from constant chewing.

Hypsodont

high crown, enamel extends deeply past the gum line

• extra surface for chewing

• protection for fibrous food

• in ungulates and some rodents.

Aradicular

continuously growing

• constantly replaced as constantly worn

diastema

a gap or space between teeth, often found in herbivorous animals where canines are absent or reduced, allowing for efficient grazing.

• seperating incisors from premolars