Comparative anatomy exam 3: topics 9 & 10

From the ectoderm, the stomodeum forms what?

the temporary buccopharyngeal membrane that ruptures to make combine the lumina; will form buccal cavity

Posteriorly, the proctodeum forms what?

the cloacal membrane then the cloaca (anal opening)

true or false: the lungs & swim bladder derived from the digestive tract?

true

Cheek pouches are found where?

in rodents and old world monkeys to store food

The oropharyngeal cavity is the?

the buccal and pharyngeal cavities together

What separates the buccal and pharyngeal cavities?

the palatoglossal arch

Forming the head in lamprey & hagfish

- part of stomodeum invaginates

- leave hypophyseal pouch and nasal placode outside

In lamprey and hagfish, the hypophyseal pouch and nasal placode combine to make what?

nasohypophyseal canal

The nasal placode is a cluster of cells that will become what?

the olfactory organ

forming the head in chondrichthyes and bony fish

- stomodeum invaginates to bring in hypophyseal canal inside

- nasal placodes will remain outside to form 4 nostrils

forming the head in osteolepimorphs & tetrapods

- stomodeum invaginates to bring in both the nasal placodes and hypophyseal canal

the palate is?

the roof of the buccal cavity

There are 2 types of palates, what are they?

primary & secondary palates

the primary palate includes what?

vomer, pterygoids, parasphenoids, palatines and ectopterygoids

true or false: the primary palate had no holes until osteolepimorphs?

true

the secondary palate includes what?

premaxilla, maxilla, and palatines

the secondary palate allows us to do what function?

to chew and breathe at the same time

what organisms is the secondary palate found in?

crocodilians and mammals

what unique substance are teeth capped with?

enamel

how do teeth form?

from induction b/w embryonic epidermis and neural crest derived mesenchyme

the epidermis forms what for teeth?

enamel

The mesenchyme forms what for teeth?

dentin

enamel and dentin work together to make what for us?

teeth

outside in hypothesis in teeth

teeth derived from odontodes or integumentary teeth

inside out hypothesis in teeth

teeth arise from pharyngeal jaws

Gingiva is ?

the gum line

above the gingiva is the?

crown

below the gingiva is?

the base or a root if it fits in a socket

What is the mucous connective tissue inside the tooth that helps support it?

the pulp

the enamel organ forms where to make what?

forms in the epidermis to make enamel

the mesenchyme from the neural crest forms what?

the dermal papilla to make dentin

order of appearance of tooth parts?

crown, root, cementum and periodontal ligament

Tongues in hagfishes and lampreys are formed from?

the floor of the pharynx and have kerantinized teeth

In tetrapods, the tongue is derived from?

hypobranchial musculature & is operated by the hyoid apparatus

Intraoral transport is?

ability to move food into the mouth via the tongue; needs wet adhesion to do so

What are the 3 seals mammals use when chewing to help control the passage of food?

1. Anterior: lips

2. Middle: between soft palate & tongue

3. between epiglottis & soft palate

posterior seal function in mammals & human infants

- to ensure passage of food without blocking air

- in human infants: to direct milk to esophagus

True or false: the posterior seal is lost in adults because the pharynx descends for speech which makes it easier for humans to choke compared to other mammals

true

Hagfish & lamprey intestinal system

no stomach, have a single intestine and have folds in the lumen

Chondrichthyes intestinal system

have spiral valve intestine to increase absorptive area

foregut fermenters characteristics

- red kangaroos & camels

- have pits in their stomach for fermentation

True or false: ruminants are a type of foregut fermenter?

true

Ruminant characteristics

- includes deer, giraffe, and cow families

- have 4 chambered stomachs

The hindgut fermenters include

horses, rabbits, pigs, koalas, reptiles, birds and many amphibians

When does liver development begin?

when the fibroblast growth factor is produced by the cardiac mesoderm

What turns on liver development?

fibroblast growth factor and bone morphogenic proteins

the gallbladder is present/absent in what organisms?

- present in most mammals, birds, and bovids

- absent in hagfish, lamprey and cervids

Intestine functions

- move food

- mucus protection from digestive enzymes

receive proteolytic enzymes from pancreas

- absorb products of digestion & water

In the intestines, what neutralizes chyme?

duodenal or brunner's glands

What substances enter the duodenum?

- chyme from stomach

- exocrine secretions from liver and pancreas

What does the jejunum absorb?

carbs and proteins

What's the sphincter that regulates movement into the large intestine?

Ileocolic valve

Urinary system functions

- maintain water

- get rid of nitrogenous waste

- maintain ion balance

- get rid of toxic materials and excess nutrients

direction of urine in kidneys

1. minor calyx

2. major calyx

3. renal pelvis

4. ureter

5. urinary bladder

6. urethra

true or false: kidney arrangement is fairly similar across all vertebrates?

true

what is the first step in kidney development?

the nephric ridge forms

Nephrotomes grow into the renal capsule. What will the renal capsule become?

glomerulus

Pronephros are present and active in what organisms?

- juvenile hagfish

- larval lampreys and amphibians

- embryonic jawed fish

The tubules that form anteriorly first are called?

pronephros

The 3 different forms in nitrogen excretion is ?

uricotelism, ammonotelism and urotelism

Ammonotelism characteristics

- excrete ammonia rapidly through skin/gills

- only works in water

uricotelism characteristics

- produce urea (less toxic than ammonia)

- uric acid isn't soluble

urotelism characteristics

- urea can be stored & concenrated

- lungfish can use when aestivating

aquatic animals typically use what type of nitrogen excretion?

ammonotelism

Mammals, amphibians, sarcopterygian fish, sharks and coelacanths use what type of nitrogen excretion?

urotelism

what organisms are osmoconformers?

hagfish, chondrichthyes and coelacanths

osmoconformers are?

organisms that are isosmotic; they can maintain the same ion concentration as the seawater

There are 2 types of osmoregulators. What are they?

hyperosmotic and hyposmotic

Hyperosmotic characteristics

- body saltier than water

- water in and salts out

Hyposmotic characteristics

- body less salty than water

- water out, salts in

- lose distal convoluted tubule

Testosterone stimulates the development of the Wolffian duct into what?

the vas deferens, epididymis, prostate, and seminal vesicles

In females what does the Mullerian duct become?

oviducts, uterus, and vagina; wolffian duct will regress

hagfish and lamprey female repro system

- hagfish: have 1 ovary suspended middorsally

- no oviduct so eggs are released into coelom

Metatherian uterus

- dupex uterus w/ 2 distinct horns

- have 2 vaginas & 2 cervices

Eutherian uterus

- 2 uterine horns, 2 cervices & 1 vagina

- urethra & vagina combine

- shows gradual fusion of uterine horns in several groups

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