Blood Vessels Arteries carry blood away from heart Ventral aorta Dorsal aorta Aortic arches between the two

Key Points There are 7 visceral arches and yet the previous slide only showed 6 aortic arches, why?

Ventral aorta & Aortic Arches Fish Afferent branchial artery Gill capillaries Efferent branchial artery Teleosts – 1 & 2 are gone Lungfish – Pulmonary artery is branch from 6th aortic arch – efferent region

Tetrapod Ventral Aorta & Aortic Arches General pattern 6 arches in embryo 1 & 2 rapidly regress Internal carotid artery is formed from arch 3 plus paired dorsal aortae Fifth aortic arch is gone in most

Tetrapod Ventral aorta & Aortic Arches Pulmonary artery is a branch from arch 6 Common carotid artery is from ventral aorta External carotid artery is from common carotid artery

Amphibian Ventral Aorta & Aortic Arches Urodeles have ductus caroticus present meaning blood in arch three can go cranial or caudal Anurans have no ductus caroticus, so that blood in third aortic arch can only go towards the head

Reptile Ventral Aorta & Aortic Arches Two aortic trunks from conus arteriosus – sends blood to arch 3 and 4 One pulmonary trunk from conus arteriosus – sends blood to 6th aortic arch Otherwise similar to amphibians

Birds & Mammals Ventral Aorta & Aortic Arches One aortic trunk that sends blood to arches 3 and 4 One pulmonary trunk sends blood to arch 6 Fourth Aortic Arch Right side stays in birds Left side stays in mammals Right side of 4th arch becomes subclavian A. in mammals

Bird & Mammal Ventral Aorta & Aortic Arches Ductus arteriosus is in fetus only. It is a bypass of blood from the pulmonary trunk to the aorta Carotids have same general pattern

Key Points Why would the mammalian fetus need a bypass from the pulmonary trunk to the aorta?

Dorsal Aorta General Pattern Paired in head & pharynx in embryo and stays paired in adult as internal carotid arteries Single in trunk Becomes the caudal artery

Key Points Where do you find the caudal artery in the shark? Compare its location with the notochord and the nerve cord.

Dorsal Aorta Ventral Visceral branches Celiac A. supplies stomach, pancreas, liver Mesenteric A. supplies intestine (may be more than one)

Dorsal Aorta Lateral visceral branches Urogenital

Dorsal Aorta Somatic branches to skin, spine, muscles Subclavian A  Brachial A. supplies arm Iliac A  Femoral A. supplies leg

Veins Veins start as capillaries and carry blood towards the heart

Key Points Define artery Define capillary Define vein Define trunk Define sinus

Cardinal Stream Sharks Common Cardinal Vein Anterior cardinal vein – drains head Posterior cardinal vein drains kidney, body wall, gonads, and most of body except digestive structures

Key Points Trace the blood flow from the shark’s kidney to its ventral aorta.

Cardinal Stream Amphibians Most of postcardinal disappears in anurans, but persists in urodeles

Cardinal Stream Amniotes Postcava (=inferior vena cava = caudal vena cava) Takes the place of the Posterior Cardinal Vein Drains some of hindlimbs in crocodiles, all of hindlimbs in mammals and eventually drains most of trunk and tail, in addition to hind limbs

Cardinal Stream in Amniotes Azygous/Hemiazygous From R. Posterior Cardinal V. Provides alternate route from structures caudal to diaphragm Mammals only

Cardinal Stream in Amniotes Precava (= superior vena cava = cranial vena cava) From Common Cardinal Vein In cats and humans, Right Precava persists and lose most of left.

Cardinal Stream in Amniotes Internal Jugular Vein Drains brain From the Anterior Cardinal Vein

Key Points Trace the blood flow from the brain of a crocodile to the sinus venosus.

Renal Portal Stream A Portal is a vein that begins and ends in a capillary bed Fish – drains tail to kidney Amphibians – drains hindlimbs to kidneys Reptiles and birds – bypasses kidneys and goes to postcava Mammals –not present

Key Points Where are the capillary beds for the Renal Portal Veins in the shark?

Abdominal Stream Sharks Lateral abdominal Veins are paired Iliac V. from pelvic fins Subclavian V from pectoral fins eventually to common cardinal V.

Key Points Trace the blood flow from the shark’s pectoral fin back to the sinus venosus of the heart.

Abdominal Stream Amphibians Ventral – single vessel, not paired as in fish No connection to forelimbs

Abdominal Stream Reptiles Paired abdominal V No connection to forelimbs

Abdominal Stream Mammals In fetus only Umbilical Vein becomes the round ligament of the liver in the adult Ductus venosus is a bypass of the liver and becomes the ligament venosum as a remnant in the adult

Key Points Summarize the evolutionary trend for venous drainage of the forelimb. Shark Anurans Amniotes

Key Points Summarize the evolutionary trend of venous drainage of the hindlimbs Fish Amphibians Reptiles Mammals

Hepatic Portal Stream & Hepatic Sinuses All vertebrates have this Similar in all What is a sinus?

Hepatic Portal Stream & Hepatic Sinuses Vitelline V. from yolk sac to heart early in development Subintestinal Vein from digestive visceral to vitelline Vein

Hepatic Portal Stream & Hepatic Sinuses Hepatic Portal System – develops from one Vitelline V. and Subintestinal V. Hepatic Sinuses – develop within liver from vitelline veins

Mammalian Fetal Circulation Ductus venosus is bypass of liver Ductus arteriosus and foramen ovale of interatrial septum are bypasses of lungs

Key Points Why is there a liver bypass in mammal fetus? Why is there a lung bypass in mammal fetus?