Comparative Anatomy Circulatory System...Comparative Anatomy Digestive System By: Vahid Akmali Email:[email protected] 3/19/2020 By: Dr Somayeh Esmaeili Rineh 33 Digestive System

Comparative Anatomy

Circulatory System

13/19/2020 By: Dr Somayeh Esmaeili Rineh

Circulatory System

The circulatory system consists of a blood vascular system and

a lymphatic system.

The blood vascular system consists of whole blood, heart,

arteries, capillaries, and veins.

Blood consists of plasma and formed elements. The

formed elements are erythrocytes, granular and

agranular leukocytes (the latter includes lymphocytes), and

thrombocytes (platelets).

Hemocytoblasts are precursors of all blood cells.

Their initial source is blood islands of the yolk sac.

Eventually they form in liver, kidney, spleen, and

bone marrow.23/19/2020 By: Dr Somayeh Esmaeili Rineh

Circulatory System

Aortic arches- within pharyngeal arches

Arteries

Carries blood away from heart

Muscular, elastic fibrous walls

Regulates blood pressure

Terminate in capillary bed

Veins

Carry blood toward heart, fibrouse tissue

Heart

Modified blood vessel

Figure 13.1: Cross section of

artery and vein.


Portal Systems

Veins drain organ and dump blood into other

organ instead of heart

Figure 13.4: Portal systems.43/19/2020 By: Dr Somayeh Esmaeili Rineh

Portal Systems (cont.)

Hepatic

Drains intestine into liver

Renal

Drains venous channels of

tail into kidneys

Hypophyseal

Drains hypothalamus into

sinusoids of anterior pituitary

Figure 13.5: Hepatic and renal portal systems. 53/19/2020 By: Dr Somayeh Esmaeili Rineh

Typical tetrapod blood pumped

By pulmonary arteries, from heart to lungs

By pulmonary veins, back to heart

Heart


Heart (cont.)

Figure 13.7: Chambers of the primitive vertebrate heart. 73/19/2020 By: Dr Somayeh Esmaeili Rineh

Heart (cont.)

Figure 13.8: The heart tube elongates and bends.


Fish Heart

Fish heart- tube like

4 chambers:

Sinus venosus

Atrium

Ventricle

Conus arteriosus

Figure 13.9: Four chambered heart.


single-circuit heart.

Fishes

Venous blood enters a sinus

venosus. traverses an atrium,

ventricle, and conus

arteriosus.

The last two are pumps

that discharge into a ventral

aorta.

The latter carries blood to

aortic arches that supply gills,

where blood is oxygenated.

It then passes via arteries

to

capillaries everywhere in

the body, gives up

oxygen, takes on carbon

dioxide, and returns to

the sinus venosus.


double-circuit heart

In craniates that breathe solely

by lungs, a pulmonary circuit

carries blood to the lungs and

back

and a systemic circuit carries

oxygenated blood

elsewhere and returns

deoxygenated blood to the

heart. This is a double-circuit

heart.

Double-circuit hearts

have two atria and one or

two ventricles.

The right atrium receives

deoxygenated

blood from the systemic

circuit; the left receives

oxygenated blood from

the pulmonary circuit.


Figure 13.10: Heart chambers, oxygenated blood flow (red), and septum modification.

Heart


Lungfish and Amphibian vs Dogfish

Modifications of partial or complete partition in

atrium

Left and right atria

Advent of lungs

Double circulation

Modification in conus arteriosus

spiral valve to shunt deoxygenated blood to lungs


Spiral Valve

Figure 13.11: Spiral valve in

dipnoans; longitudinal folds

of conus lining.

Figure 13.12: Spiral valve in anurans; single flap.


Amphibian Heart

Spiral valve directs oxy. blood

entering ventricle from left

atrium

Conus (truncus) arteriosus;

Bulbous arteriosus

Swelling of ventral aorta

Smooth muscle

Figure 13.13: Three-chambered frog heart.


Urodele- partially

divided circulation

Right and left atrium

Sinus venosus dumps

into right atrium

Pulmonary veins leave

left ventricle

Reptile - fully divided

circulation, but

additional chamber (as

in turtle)

Figure 13.14: Turtle heart chambers and

circulation path.

Amphibian Heart (cont.)


Reptile Heart

Cavum venosum (CV)- internal pocket; e.g., turtle

Blood collected from post cava through sinus venosus

to precava

To right atrium

Venous blood to CV

Cavum pulmonale

Into pulmonary artery to lungs

Oxy. blood returns through pulmonary veins in left atrium

Back to CV

To left and right aortic trunk


Blood Circulation

Figure 13.15: Single loop fish and double loop amphibian and mammal circulation.


Amniote Heart

4 chambered heart

2 atria and 2 ventricles

Birds and mammals

Sinus venosus- 5th chamber in reptile heart

Becomes sino-atrial node

In embryo, right and left atria are not separated

Auricle - flap on side of atrium


Aortic Arches

Basic pattern has 6 aortic arches

Major arterial channels

Ventral aorta

Dorsal aorta

6 pairs of aortic arches connects ventral and dorsal

aorta

Reptiles - additional aortic trunk


Aortic Arches (cont.)

Figure 13.21: Ventral perspective of aortic

arches.

Figure 13.20: Basic pattern of

aortic arches and dorsal aortae.



Figure 13.22: Left aortic arches. 233/19/2020 By: Dr Somayeh Esmaeili Rineh

Aortic Arches (cont.)

Teleost

1st and 2nd arches lost

Dorsal aortae become internal

carotids

Lung fish

Pulmonary artery from 6th arch

Tetrapods

Pulmonary artery from 6th arch

5th arch lost Figure 13.23: Aortic arches, internal

carotids (ic) and pulmonary artery.


Tetrapod Aortic Arches

1st and 2nd arches lost

Dorsal segment dropped

between 3rd and 4th arches

Ductus caroticus

Figure 13.24: Adult aortic arches

(book figure 14.19).


Tetrapod Aortic Arches (cont.)

3rd arch extends to internal

carotids

Carotid arch

Ventral aorta extension

External carotid

Common carotid at base

between 3rd and 4thFigure 13.25: Aortic arches, internal

carotid (ic), external carotid (ec) and

common carotid (cc).


Tetrapod Aortic Arches (cont.)

5th arch lost

Dorsal segment of 6th arch lost

4th arch- no anterior connection

Aortic arch

6th arch

Pulmonary arch

Ex: adult anuran

Figure 13.26: Adult aortic

arches.


Figure 13.27: Modifications of aortic arches

and dorsal aortae into mature vascular system.


Aortic Arches

Urodele Ductus caroticus

Ductus arteriosus- dorsal segment of 6th arch

Reptiles 1st and 2nd arches lost

Ductus caroticus lost

5th arch lost

Ductus arteriosus lost

Additional aortic arch introduced

Arch from left side loops right

Arch from right side loops left


Mammalian Aortic Arches

3rd, 4th, 5th, & 6th retained

embryonically

Adults- 1st and 2nd dropped

3rd carotid arch

4th systemic arch

5th lost

Dorsal segment of 6th lost

Retained embryonically- ductus

arteriosus (becomes ligamentum

arteriosum)

Figure 13.28: Adult aortic

arches.

Figure 13.29: Left aortic arches.303/19/2020 By: Dr Somayeh Esmaeili Rineh

Bird Aortic Arches

Right portion of

aortic arch is

retained and left is

lost (opposite to

mammals)

Birds have right

aortic arch

Mammals have left

aortic arch313/19/2020 By: Dr Somayeh Esmaeili Rineh

A sinus venosus is present in fishes, amphibians,

and reptiles.

It becomes partially incorporated into

the wall of the right atrium in crocodilians.

In birds and mammals, it is not a sinus but a

local collection of cells in the right atrium

known as the sinoatrial (SA) node.


Comparative Anatomy

Digestive System

By: Vahid Akmali

Email:[email protected]


Digestive System

Six major subdivisions

Oral cavity

Pharynx

Esophagus

Stomach

Small & large intestine

Rectum


Digestive System

Agnatha - straight

digestive tube

Coiled tube evolved with

lengthening of tract

Figure 11.1: Simple to complex digestive

systems. 353/19/2020 By: Dr Somayeh Esmaeili Rineh

1- Esophagus

2- Stomach

3- Duodenum

4- intestine

5- Small intestine

6- large intestine

7- Colon

8- Rectum


Oral Cavity

Begins at mouth, ends at

pharynx

Tongue in floor of cavity

Palate in roof of cavity

Primary palate

Secondary palate

Teeth

Figure 11.2: Human oral cavity.


Palates

Primary palate in

anamniotes- nasal

passageways empty into oral

cavity

Ex: Salamander

Secondary palate of

amniotes- extends to

pharyngeal cavity

Internal naresFigure 11.3: Oral cavity of

amphibian (a) and mammal (b).383/19/2020 By: Dr Somayeh Esmaeili Rineh

Teeth On jaws normally

Cheeks in mammals form pocket

Acrodont teeth- fish and snakes

Bicuspid- amphibians

Tricuspid- lizards

Pleurodont teeth- snakes

Thecodont teeth-

crocodilians

Figure 11.4- Cross section of jaw.Figure 11.5- Types of cusps.



Jaw Teeth and Cheek

Modified placoid scales- sharks

Polyhyodont- permanent replacement of teeth

Diphyodont- two sets of teeth

Monophyodont- one set of teeth


Epidermal Teeth

Egg teeth all egg layers

Not actual tooth

Structure epidermal, horny,

keratinized

On tip of snout

To penetrate egg shell

Bird, turtle, crocodile, Sphenodon

& monotrems

Figure 11.6: Egg caruncle of 15 day

old owlet. 423/19/2020 By: Dr Somayeh Esmaeili Rineh

Incisors

For cutting

Ex: elephant tusks

Canines

For piercing

Ex: walrus tusks

Premolars & Molars

To matriculate food

Diastema- space without

teeth; e.g., no canines

Figure 11.9: Mammalian teeth

specializations.

Mammalian Teeth


Tongue

Immobile in jawed fish

Fleshy in higher vertebrates

Frog- tongue shoots out and draws

back

Glandular field secretes sticky fluid

Immobile tongue- turtles, crocs,

and some birds

Flexible tongue- nectar feeding

bats and snakes

Forked tongue of snake

Figure 11.11: Jacobson’s organ (sensing

apparatus) of snake and forked tongue.443/19/2020 By: Dr Somayeh Esmaeili Rineh

Oral Glands

Named based on location

Labial- near the lips

Palatal- near palate

Internasal

Sublingual- releases venom

Parotid- salivary gland

Submaxillary

Birds have few oral glands

Swifts Figure 11.12: Swift and nest.


Pharynx

In embryo, exhibits series of lateral

pharyngeal pouches

Gives rise to various glands

Slits in pharyngeal region

Figure 11.13: Embryonic pharyngeal

arches and oral development.Figure 11.14: Adult regions of pharynx.



Esophagus

Muscular tube connecting pharynx

and stomach

Can be short

Crop- specialization in birds

Outpocketing of esophagus

Used to store food

Pigeon’s milk

Figure 11.16: Esophagus and

crop of bird.483/19/2020 By: Dr Somayeh Esmaeili Rineh

Stomach Muscular chamber

Secretes gastric juices

Different lining of stomachs

Esophageal-like epithelia

Glandular epithelia

Ruminant stomach

4 chambers: rumen, reticulum,

omasum, abomasum

Human stomach

Cardiac sphincter- esophagus

meets stomach

Mostly lined with gastric epithelium

Figure 11.17: Stomach of mammals with

esophageal-like epithelia in gray and glandular

epithelia in red.


Stomach Structure

Greater and lesser curvature

Messentaries

Greater omentum – attaches along greater curvature

Lesser omentum – attaches along lesser curvature

Cecum- increases surface area

2 parts in bird and crocodile stomach

Proventiculus-glandular

Gizzard- grinding mill (gastroliths)


4-Chambered Stomachs

Figure 11.18: Stomach of calf.

Rumen- food enters

Bacterial action

Reticulum- fermentation-

forms a bolus

Omasum- reswallowed grass

Salivary action

Abomasum- food worked out

by gastric glands


Small Intestine

Duodenum- 1st segment

Bile and pancreatic ducts

Jejunum and Ileum

subdivisions

Figure 11.19: Digestive tract showing

regions of small intestine.523/19/2020 By: Dr Somayeh Esmaeili Rineh

Brunner’s Glands- mucous glands in duodenum

and jejunum

Peyer’s Patches- lymphatic nodules in ileum

Crypts of Lieberkühns- intestinal glands at base

of villi

Lacteals- within villi—interior lymphatic vessels

Transport fat molecules to circulatory system

Valve of Kirckring- increases surface area

Small Intestine


Small Intestine

Figure 11.20: Histology of alimentary canal of a mammal

showing various glands of small intestine.


Large Intestine

Fish and amphibians - straight and short

Amniotes- divided into colon and rectum

Ileocecal valve- allows passage from small intestine into large

Sigmoid flexure- S-shaped region

at rectum

Cecum- aids in absorption

Terminates at vermiform appendix

Figure 11.21: Large intestine of human.553/19/2020 By: Dr Somayeh Esmaeili Rineh

Liver

Liver is diverticulum of primitive gut

Liver produces bile

Bile stored in gallbladder

Common bile duct

Ampulla of Vater- terminal portion

Figure 11.22: Development of liver and pancreas. 563/19/2020 By: Dr Somayeh Esmaeili Rineh

Pancreas

Pancreas – diverticulum of gut

Duct of Santorini- small, dorsal pancreas

Duct of Wirsung- large, ventral pancreas

Accessory duct- large duct after small, dorsal

duct disappears

Exocrine and endocrine glands

Islets of Langerhans- endocrine glands


Documents

Comparative Anatomy Circulatory System...Comparative Anatomy Digestive System By: Vahid Akmali Email:[email protected] 3/19/2020 By: Dr Somayeh Esmaeili Rineh 33 Digestive System