Study guide 3.docx

Test 3 Study Objectives

1. Describe the distinguishing characteristics of the structure of smooth muscle, striated muscle and cardiac muscle, and name the embryonic tissue layer from which muscle is derived. Muscle Type Defining CharacteristicsEmbryonic Layer from which muscle is derived

Smooth Muscle Looks different and occurs in different places Spindle shaped cells Single nucleus No banding patterns/striations Occur in thin sheets of muscle in walls of organ, blood vessels and tissues Makes up muscle that is under involuntary control Entirely conserved with visceral muscles- might be considered as a type of visceral muscle Can be influenced by hormones Electrically coupled- one muscle to anotherOf the GI tract: Splanchnic mesodermsurrounding the endoderm of theprimitive gut and its outgrowthsWalls of blood vessels+lymphatic channel:Somatic mesodermIris and Mammary glands:Ectoderm

Local mesenchyme

Striated Muscle Cylindrical cells Multiple nuclei in each striated cell Banding patterns/ striations present : product of arrangement of contractile elements in muscle tissue Makes up muscle that is under voluntary control Ex: Cardiac muscle

Splanchnic mesoderm

Cardiac Muscle Multinucleated, Nuclei are located centrally Cells are branched/ woven together Multinucleated, but the nucleus is centrally located No striation Makes up muscle that is under involuntary control Innate tendency to contract Specialized conduction system Intercalated disks: place where two cells meet, allows rapid transmission of signals from one cell to the next Only found in the heartSplanchnic mesoderm surrounding the early endocardial heart tube

2. Name and describe the types of muscles that are categorized as skeletal muscles and that are categorized as non-skeletal musclesMuscle TypeDefining CharacteristicsEmbryonic layer from which muscle is derived

Skeletal Muscle Skeletal Muscles Trunk and tail Associated with the vertebral column They are the Myotome of somite that grows ventrally during the development of the vertebrae They make a connection with the vertebrate and they are supplied by spinal nerves Metameric and form blocks (it gets less visible as we move up in time) Divides into hypaxial and epaxial muscles In tetrapods the muscles are much more developed From 3 layers External oblique Internal oblique Transverse septum Hypaxial muscles become more important for locomotion and the epaxial muscles are not that important and become less developed. Fish Trunk Muscles They are metameric and form visible blocks The myosepta becomes attached to the axial skeleton There is visible horizontal septum that divides into the epaxial and hypaxial muscles. Epaxial muscles are more developed because they are responsible for locomotion Tail musculature is important because it is the one that helps propel the fish. And it is derived to be strong Amphibians Epaxial muscles are still one muscle Hypaxial muscles become more derived and segmented You can see traces of the horiztontal septum Reptiles Horizaontal septum is lost Epaxial musculature is lost more Hypaxial muscle becomes more assoiciated with the body segment The epaxial muscle is divided into the dorsomedial, medial, and lateral Tetrapods You see development of obliques Highly developed hypaxial muscles No horizontal septum

Non-skeletal muscle Extrinsic eye muscles There are 6 extrinsic eye muscels Superior/inferior oblique Superior/inferior rectus Medial/lateral rectus Supplied by cranial nerves-not spinal nerves Derived from Myotome and part of somites Preotic somites give rise to the 6 muscles They are skeletal muscles that allow the eyeball to move Hypobranchial muscles and tongue muscles in tetrapods They are located ventral to the pharynx The from somite buds They form the floor of the pharynx (also gill arches) and they also surround the pericardial cavity They are associated with movement of jaw and gill slit Muscles in the tongue are derived from Hypobranchial muscles Innervated by spinal nerves Appendicular 2 types- extrinsic and intrinsic Involves the appendages and the paired fins and any muscles associated with any unpaired fins in fishes Extrinsic muscles are muscle that attach to the limb or girdle in the axial skeleton When they contract they move the limb entirely Intrinsic muscles occur completely within the limb or girdle and when they contact they only move part of the appendage relative to the other part of the appendage Example finger muscles Develop from blastemas from the hypaxial Appendicular muscles are not well developed in fish because there is no heavy movement of the fins In tetrapods appendicular muscles become much more important and they change drastically Limbs arise from blastemas that developed that appear within the limb bud that give rise to the intrinsic muscles Extrinsic muscle comes from blastemas migration in hypaxial myotems maintain connect with the skeleton Innervated by spinal nerves Fishess Not well developed because the fish used its axial musculature for locomotion, and they only supported the paired fin Tetrapods Two opposing muscles, dorsal and ventral Much more distinct muscles due to locomotion Birds Axial decreases and appendicular muscles increase They are bunched proximally due to flight and landing Wing muscles are more powered for flight Integumentary Muscles associated with the integument Some are extrinsic muscles because they are attached to the skeleton Striated Allows movement of skin Facial expression Pull lip back Temporal portion of skull Intrinsic muscles Entirely within the integument Occur in birds and mammals Moves the hair or feathers Branchiomeric muscles They are muscles associated with the pharyngeal arch Visceral muscles because they are derived from splanich mesoderm They are voluntary and striated Occur in pharyngeal arches Skeletal elements are associated with these Innervated by cranial nerves Function in jaw movement, gill movement, hyoid apparatus movement, facial muscles, neck and throat muscles, and larynx. Important feeding apparatus in fishes Helps with pumping of water Electric Organs They are capable of producing electric discharges in vertebrate Some are myotomic and some are Branchiomeric This suggest that this arose more than one time in evolution Produce low voltage Used for radar Navigation Signaling Able to do this by mormyomasts: receptor cells in the lateral system and ear that detect electric field changes around them Made of many stacks of thin muscle fibers The charge is on one face of the muscle

3. Name and describe the origin of muscles that are categorized as somatic muscles and those that are categorized as visceral muscles; describe the differences between somatic and visceral muscle

Somatic Muscle vs. Visceral Muscle

Somatic MuscleVisceral Muscle

- Origin made of bone- Insertion is the dermis- Derived from myotome somite in developing vertebrae- Muscles that control the activity of organs, vessels or ducts- Derived from splanchnic mesoderm

4. Describe the ontogeny of trunk muscle and the distinguishing features of the trunk musculature in fishes and tetrapods; identify the important trend inthe evolution of trunk musculature in vertebrates.

Ontogeny

Myotome of the somite, it grows ventrally and we get this ventral growth and as development process we get development of the vertebrae in the midline and they go all the way down to the ventral part of the body and the meet each other and they make the linea alba and you get further development as this proceeds This Myotome make a connection with the vertebrate and they are supplied from nerves from the spinal nerve and its associated with the region with two associated vertebrate. They are metameric because they form blocks By the time we look at a fish, you can see the nature of the trunk muscles divided into the dorsal (epaxial) and ventral (hypaxial) muscles. Each segment represents a Myotome from a somite and they are skeletal muscles In anamiote you see the horizontal septa In tetrapods, muscles are much more developed and you dont see a horizontal septa, instead you see 3 layers of muscles called the external oblique, internal oblique, and transverse septum Evolution of trunk musculature in vertebrates

How the trunk and tail musculature has changed phylogenetically

In fish this muscles are particular critical for producing locomotion and these muscles are extremely well developed (divided to hypaxial, epaxial, and a sheet in between) because of the role they play in locomotion In tetrapods locomotion is associated with the muscles associated with the appendages and the hypaxial muscles tend not to be quite developed, the exception is the semi aquatic forms In amphibians and amniotes, hypaxial muscles tend to be divided into 3 distinct layers that we see in the cat External oblique Internal oblique Transverse muscles are in between. Support the abdomen against gravity Because they are secondarily adapted and highly derived for life in water, some of those characteristics are not well developed

One of the other aspects that we look at is the presence of a specialized structure called the diaphragm

The muscles in the diaphragm there is a basic connective tissue structure in rep and birds that dont have all of this muscle than in the mammal, the muscle comes from myomeres up in the neck region anterior to where we see the formation of diaphragm The muscles that provide the musculature of the diaphragm comes from myomeres from somite and the nerves that innervate the diagraph are spinal nerves So structures that are derived from myomeres are innervated with spinal nerves As we go from fish to tetrapods, the myomeres instead of retaining that clear segmentation tend to start to get thicker and the myosepta in between each of them, begins to disappear. This will blur this basic segmental appearance, or metamerism

5. Explain what the hypobranchial musculature is and its derivation.Hypobranchial and tongue muscles Ventral to the pharynx They are posterior to the pharynx and the buds grow forward, beneath the pharynx this is the origin. They form from somite that are posterior to the pharynx and buds from under it beneath it or hypo The muscles are innervated by spinal nerves They grow beneath, forward, ventral to the pharynx, and obviously they will be different in fish than tetrapods because of the presence of the pharnx They form the floor of the pharynx, but also they are surrounding the pericardial cavity The pharynx is associated with movement of jaw and gill slits movement In tetrapods, there are a lot of derivations, we get the development of larynx (voice box) that allows us to make sounds We also develop a movable tongue compacted to fish (supported by hyoid apparatus and some of the muscles are derived from the Hypobranchial muscles Muscles in the tongue itself are also derived from these muscles. Again, these are innervated by spinal nerves and they are derived from Myotome that are posterior to the pharyngeal region and are also innervated by spinal nerves In necturus ventral view you see the Hypobranchial muscles

6. Describe the derivation of the diaphragm and its innervation and name the vertebrate group in which it occurs.One of the other aspects that we look at is the presence of a specialized structure called the diaphragm The muscles in the diaphragm there is a basic connective tissue structure in rep and birds that dont have all of this muscle than in the mammal, the muscle comes from myomeres up in the neck region anterior to where we see the formation of diaphragm The muscles that provide the musculature of the diaphragm comes from myomeres from somite and the nerves that innervate the diagraph are spinal nerves So structures that are derived from myomeres are innervated with spinal nerves As we go from fish to tetrapods, the myomeres instead of retaining that clear segmentation tend to start to get thicker and the myosepta in between each of them, begins to disappear. This will blur this basic segmental appearance, or metamerism

7. Based on our discussion in class, describe the derivation of the extrinsic muscles and name the type of nerves supplying these eye muscles. Extrinsic Eye Muscles 6 muscles superior oblique, inferior oblique, superior recturs, lateral rectus. inferor rectus, superior rectus Also derived from Myotome and parts of somites Somites that give rise to these 6 muscles are the preotic somites (before the ear) These attach from the orbit onto the eye Skeletal muscles Allow movement of eyeball relative to socket There are muscle in amniotes that are movable and they are also associated with the preotic somites They are innervated by cranial nerve We can see the 3 preotic Myotome and the otic capsule, otic capsule and the nasal capsule They are in close association with the otic capsule

8. Differentiate between extrinsic and intrinsic appendicular muscles and identify the type of nerves innervating appendicular muscles. Extrinsic appendicular muscles are muscles that attach to the limb or the girdle in axial skeleton Extrinsic muscle derives from the somites in the Myotome that become the muscles of the trunk and tail region associated with the axial skeleton. Intrinsci appendicular muscles are mucles that occur completely within the limb or girdle. They move part of the appendage apart relative to the other part of the appendage. Intrisic muscles develop from blastemas from the hypaxials and then they develop as muscle within the appendage with no connection to the Myotome from the appendage itself. Nerves that innervated the appendicular muscles are spinal nerves.

9. Describe the branchiomeric musculature and identify the embryonic tissue from which it is derived. Branchiomeric Muscles Muscles associated with pharyngeal arch Visceral muscles because they are derived from splanchnic mesoderm They are voluntary and striated muscles They are the muscles that occur in pharyngeal arches These bars of tissue in between a gill slit, have some structures that are always present in them. There is the skeletal elements (bone or cartilage), aortic arches, the Branchiomeric muscle, cranial nerves, circulatory vessels, cranial nerve branches The muscle obviously that froms is innervated by cranial nerves Depending on what we are looking at, we get as many as 15 pouches with these large tissue and 6 or fewer in ganthostome vertebrates

10. Describe the function of branchiomeric muscle in fishes and in tetrapods. One of the thing that they do given the fact that we have the anterior 2 arches in jaw formation, some of these muscles have to do with the jaw Moving the gills and Moving the hyoid apparatus Some of the facial muscles, muscles that are associated with faical structures Some of the muscles of the neck and throat Also some of the muscles that operate the larynx (some are Hypobranchial muscles)

11. Explain what integumentary muscles and their appearance and functions in the vertebrate groups we discussed in class. Integumentary muscles are muscles that are associated with the integument. Some are extrinsic and some are intrinsic They attack the skeleton to the integument The end of the muscle that is less movable is the origin and the end of the muscle that is more movable is the insertion So the organ is the skeleton and the insertion is the dermis This muscle is a form of skeletal muscle and it is striated. In amniotes it is well developed and it allows movement of skin and creation of facial expressions. They are also part of the muscles that are associated with the lip and they move the lip back Intrinsic integumentary muscles These are muscles that occur entirely within the integument- there is no origin in the skeleton- not skeleton muscles These muscles are within the dermis and they are smooth muscle

12. Describe the structure, functions, and embryonic origin of electric organs.Structures that are capable in producing electric discharges in vertebrates Electric organs are not derived from the same structures. Some are myotomic Some are Branchiomeric This suggest that they arose more than one time evolutionary Some can produce massive discharges 500-600V discharges Will give you a jolt There are also organs in other fish that produce low voltage discharges relative constant that they use for distinguishing objects around them (similar to a radar), also for navigation, signaling to other members of species if you are going to produce discharges and detect them, you detect the objects by distortion the electric field sand how it changes, so there are special receptor cells that are called mormyomasts: these are like receptor cells in the lateral line system and the ear. They are remodeled and they detect changes in electric field around the fish. If you look at how an electric organ looks like, what kind of derivation is there? How is the muscle different in the electric organ? What we will see is that an electric organ is made up of many stacks of many thin muscle fibers Each of the blue structures is a muscle fiber and in between is a gel like matrix that separates them they stack one on top of the other with the gel matrix separating, and each plate has nerve input to only to one side Basically if you look at the drawing, at rest the cells are (-) on the inside relative to the outside You can see that the outside is )+84mV) If you look at what happens when the nerve fires, only one side of the membrane depolarizes the outside becomes negative relative to the inside. Difference between the faces is (-151mV) these charges are intensified because many are stacked in series and the result is the electric force magnified

13. Describe 5 properties of respiratory membranes or organs. The primary function is that they provide a large surface area They are well vascularized because gas exchange happens between the blood and air capillaries They are moist with mucous lining to prevent particles to come in They are thin to maximize diffusion rate They provide a means of ventilating. There also has to be a mechanism to maintaining fresh air or water in contact with the surface of the membrane. This keeps the concentration gradient going and makes the rate of exchange fast.

14. Describe the formation of pharyngeal pouches and their fates in amniotes and anamniotes. During ontogeny a series of endodermal pouches form on the inside of the pharnx and start pushing outward through the mesoderm They are endodermal growth that push to the outside, as these are forming on each side of the pharnx we get these indentations called visceral furrow (outer ectorderm is pushing inward at the same places) Eventually the furrow and the pouch meet and they push through the wall of the pharynx and produce pharyngeal slits or clefts There is a connectiong with the outside and interior of pharnx Amniotes: They first pair forms the middle ear and the Eustachian tube, the rest 3-4 pairs disappear Anamiote: Gills

15. Name the structure from which lungs and swim bladders arise and identify the vertebrate group in which such a structure first appeared. Both form from out pouchings from the pharynx and they are homologous In fish this makes swim bladders, in tetrapods, these are the source of lungs We first see structures like this in placoderm and the first jawed vertebrates have this capability of developing swim bladders

16. Describe the embryonic origin of the lungs. The nature of the lungs is different. The first sign of developing bud is a little bud that grows out the ventral part of the pharynx It starts of as one bud, keeps growing posteriorly, and then it eventually divides into 2 buds once it gets to a certain point. This part of the bud that is not divided becomes the trachea which is the opening from the pharynx into the lungs and the trachea in tetrapods is generally the walls of the trachea is fibrous connective tissue and there is some fibrous muscle in the trachea. There is a mucous membrane lining it and the lining is kept moist and the thick mucous helps trap any matter that may be present in the air that is going down into the lungs

17. Describe the structure of the lungs of amphibians, reptiles, birds and mammals, explaining how the lungs of each group are ventilated/inflated.LUNGS IN FISH Lungs are basically swim bladders they get into the lung by just taking air into the oral cavity and force it into the swim bladder and because the walls of the bladders are elastic, once that pressure is released, the bladder will just rebound and push the air back into the mouth cavity The fish that is doing this has to go into the surface We know that the lungs are simple in amphibians. Thin walled sacs that sit in the pleurtoneal cavity. They basically get air into and out of the lungs the same way fish do. They take air into the mouth cavity and close muscles to force air into the lungs and once they relax, the air rebounds. (Expiration) Amphibians Lungs are not the only players in gas exchange Can happen across the skin Simple ac like Inspiration/ expiration Reptiles Major range of structures, it can be simple or very complex like the mammalian lungs. In crocodilians, lizards and snakes you get complex lungs that have lobes and are spongier and sac like with their own separate cavity. Cloaca and cloaca bladder for gas exchange Once they have separate pleural cavities they can use a suction pump mechanism Trunk muscles to raise the ribs up and down and that expands the size of the pleural cavity and the lungs and creates a lower pressure in the lungs and the air rushes in. not a diaphragm, using the intercostal muscles to change the size of the pleural cavity When they expire and force air to leave by compressing the muscles and forcing the pressure to rise. The make the cavity larger and the lungs volume becomes larger. Bird lungs Very small and they dont expand very much. They have a high metabolic rate and high oxygen affinity One thing about the lungs is that they are very efficient All adaptations have to work together Need a rigid skeletal structure for flight so the cant have the chest to do suction pump mechanism because its will reduce the rigidity of the skeletal system. So you need very efficient lungs. They lungs have separate pleural cavities but there are extensions of the lungs that go to all parts of the body and they are called air sacs. Mammals More mundane Bronchi: branching series They branch out and get smaller (bronchioles) The bronchioles give rise to very tiny tubes called alveolar ducts They bleed into these clusters of sacs called the alveoli Thin walled sacs Alveoli They cluster on around the alveolar ducts Dense little sacs Here is where gas exchange occurs there is a single epithelial cells layer defining the sac The capillaries are formed from a single endothelial cell with fluid in the inside Thin barrier between air and blood in the capillaries The lungs are similar to the most complex form of lungs in reptiles Divided into lobes Oblique Septum One of the things we are accustomed to is that in the floor of the thoracic cavity is the diaphragm- only happens in mammals- In vertebrate reptiles there is an oblique septum not a diaphragm Its the tissue that separates the pleural cavity from the peritoneal cavity In reptiles its more of what we would call Tendonous- it has a lot of collagenous and elastin fibers in it. At the level of birds, we start to see some muscle associated with that.

18. Describe the functions of air sacs in birds.Air sacs These big sacs all over the body The air sacs are not a gas exchange site Not enough vascularization Especially the ribs and wing muscles are moving during flight, the air sacs compress and expand, the primary thing that they are doing is that they are ensuring a continuous flow of air in the lungs. Whether the bird is inhaling or exhaling there is air moving in the lungs, due to the air sacs making a continuous flow The air sacs contribute to lightness and lower density, lower flight energy, they have a high metabolic rate and produce heat and the air sacs help dissipate body heat.

19. Identify 4 structures other than lungs, swim bladders and gills that may function as gas exchange organs in vertebrates. The skin Cloacal opening/ anus Oral Cavity and Pharynx Accessory Bladders20. Identify the major components of the circulatory system and describe the functions of this system.The blood vascular system Made up of blood Made up of heart and blood vessels In vertebrates is a closed circulatory systesm There are 2 components: the pulmonary division and the systemic division The lymphatic system Made up of lymph and lymph nodes Picks up excess fluid and filters it The circulatory systems major function is for transport It carries gases in the form of O2 and CO2, nutirents, wastes, hormones, and antibodies

21. Describe the structure of the heart in fishes, lung fishes, amphibians and amniotes; describe the basic pattern of circulation through these hearts, explaining/describing modifications of the heart in lung fishes and amphibians to keep oxygenated and unoxygenated blood separate.Heart in Fishes Fishes Whether gnatostome and agnastostome we have a single circuit circulation Blood comes in to the sinuous venousus to the atrium (deoxygenated blood- from the tissues) from the atrium goes into the ventricle to the aorta to the afferent branchial arteries goes into the capillaries and oxyfication occurs then it goes to the efferent branchial arteries to dorsal aorta to everywhere else it needs to go The heart only receives and pumps the deoxygenated blood. It got enough force to go through to the branchial and systemic capillaries to back to the heart The collecting chamber is the sinous venosus. It is slightly contractile with a little bit of contractile muscle. When the ventricle contracts, it reduces the size of the blood and helps make low pressure. When the ventricle expands, it tends to increase the stuff in the pericardial cavity has some contractility but not many big function not homologous with chamber of the heart the atrium is the first region blood flows through that is considered a true chamber of the blood sac like with muscles when it relaxes it pull blood in becomes smaller when it contracts and it helps reduce pressure from the sinuous venous to the atrium and when it contracts it pushes blood into the ventricle this is controlled with valves that prevent backflow, even at low levels you have this basic system to direct blood flow through the heart the major pump is the ventricle it is very thick and very muscular so this is the main pumping contractile part of the heart. It puts enough pressure on the blood to get it through the whole system and back. Conus Arteriousus Very elastic and thick walled Several sets of valves to prevent backflow Helps maintain steady pressure when ventricle relaxes Feeds blood to the ventral aorta Ventricle Thick and muscular Major pump It has to put the pressure to get into the whole system and back Atrium Thin walled Muscular True chamber of the heart Relaxes and sucks blood in from sinous venousus Contracts and forces blood into ventricle Controlled with valves that prevent backflow Collecting chamber Sinous venosus Slightly contractile and it has little muscle Heart in Lungfishes/Amphibians OTHER TISSUES involved in gas exchange Some of the blood coming back to the blood is not deoxygenated blood, it is coming from other gas exchange sites other than gills, and now you have to deal with this new material. So solution in keeping the two blood flows separate. The heart is modified to maintain these two separate blood streams to not mix then to loose deoxygenation and we see the development of double circuit circulation but in a compromised way There is a atrial septum. It is a complete wall of tissue in amhibians that makes a right and left atrium. In lungfishes it is a partial septum that keesps the bloodstream somewhat sepereate. It keeps the blood coming from the sinous venousus from the right side and blodd coming form other areas on the left side (oxygenetaed blood) The ventricle is more problematic in lungfishes now there is a partial ventricular septum, in amphibians instead, we have trebeculae in the wall of the ventricle that helps reduce mixing, but doesnt prevent mixing. The conus arteriouss has a spiral valve. This is derived from some of the valves in the primitive conous that helps the bloodstream to stay separated. There is a reduction of the ventral aorta. This is to reduce the potential for mixing Amphibians Has traveculi, right and left atrium, and not sort of wall in the ventricle in ampbians. It is not that critical because of oxygenation in the skin Heart in amniotes This system is perfected in amniotes. We see the development of a true four chambered heart. A lot of things change. One is that the conous arterious is very reduced or disappers In reptiles there is still a sinus venousus- very reduced Birds and mammals lack a sinus venosus There are well developed valves to prevent backflow Describe the primitive pattern of arterial circulation in vertebrates and describe the evolutionary changes in the aortic arches in fishes, amphibians, birds and mammals. Primitive pattern of arterial circulation in vertebrates Arterial Channels Arteries carry blood away from the heat and they are thick. Pressure drops as blood moves away from the heart Primitive Pattern and Evolution Ventral aorta: blood leaves the heart Aortic arches: blood goes through 6 pairs of aortic arches that connect to the roots of the radices aortae Radices Aortae merges to from the dorsal aorta The dorsal aorta then distributes branches to all parts of the body Evolutionary Changes in the aortic arches in fishes, amphibians, birds, and mammals In fish, we know that there is significant adaptation for gas exchange to occur in the gills. The parts of arches on either side of gills are not directly connected. Afferent branchial arteries takes away blood. Efferent branchial arteries collect blood . We are going to see that the radiciea aortae have some anterior extension that form the internal carotid arteries In teleosts, arches 1 and 2 are lost In lungfish, arch 6 on each side, form the pulmonary arteries Trend: to the reduction in number of arches from the primitive number Tetrapods Movement from single circuit to double circuit circulation Also lose arch 5 along with 1 and 2 The ventral aorta and the radicies extend anteriorly and form the external carotid arteries The 3rd arch also joins with the anterior extension of the radix aortae to form the internal carotid arteries. Arch 4 from the systemic arch on each side It is associated with the part of the radices on each side that will form the dorsal aorta Arch 6 forms a right and left pulmonary artery Reptiles We still loose arch 1,2,5 and connection of the radix on each side. There are many vessels coming out of the ventricle. Ventral aorta has broken down to 3 trunks, that represents a huge change Pulmonary trunk Derived from old ventral aorta, and joins with arch 6 on each side. Left aortic trunk Is coming out of the right side of the ventricle crossing over to the left side to make the left systemic arch to the dorsal aorta Right aortic trunk Goes out to the left side and goes to the right systemic arch Right=deoxygenated blood from the body Left= oxygenated blood from the lungs We still have the 3rd arch and the primitive radix Birds and mammals Here we have for the first time, this beautiful double circuit circulation. It is fully adapted to carry blood from the right side to the lungs, from the left side to the body. It divides to a pulmonary trunk, but now there is only one systemic trunk (or aortic trunk). Arches 1,2,5 disarppear. Ventral aorta splits to 2 trunks. Left iv arch (birds): left subclavian artery. Right IV arch (mammals) right subclavian artery. remaining iv arch + aortic trunk: dorsal aorta. pulmonary trunk : joins vi arches which become pulmonary arteries

22. Describe the primitive pattern of arterial circulation in vertebrates and describe the evolutionary changes in the aortic arches in fishes, amphibians, birds and mammals.Primitive pattern of arterial circulation in vertebrates Arterial Channels Arteries carry blood away from the heat and they are thick. Pressure drops as blood moves away from the heart Primitive Pattern and Evolution Ventral aorta: blood leaves the heart Aortic arches: blood goes through 6 pairs of aortic arches that connect to the roots of the radices aortae Radices Aortae merges to from the dorsal aorta The dorsal aorta then distributes branches to all parts of the body Evolutionary Changes in the aortic arches in fishes, amphibians, birds, and mammals In fish, we know that there is significant adaptation for gas exchange to occur in the gills. The parts of arches on either side of gills are not directly connected. Afferent branchial arteries takes away blood. Efferent branchial arteries collect blood . We are going to see that the radiciea aortae have some anterior extension that form the internal carotid arteries In teleosts, arches 1 and 2 are lost In lungfish, arch 6 on each side, form the pulmonary arteries Trend: to the reduction in number of arches from the primitive number Tetrapods Movement from single circuit to double circuit circulation Also lose arch 5 along with 1 and 2 The ventral aorta and the radicies extend anteriorly and form the external carotid arteries The 3rd arch also joins with the anterior extension of the radix aortae to form the internal carotid arteries. Arch 4 from the systemic arch on each side It is associated with the part of the radices on each side that will form the dorsal aorta Arch 6 forms a right and left pulmonary artery Reptiles We still loose arch 1,2,5 and connection of the radix on each side. There are many vessels coming out of the ventricle. Ventral aorta has broken down to 3 trunks, that represents a huge change Pulmonary trunk Derived from old ventral aorta, and joins with arch 6 on each side. Left aortic trunk Is coming out of the right side of the ventricle crossing over to the left side to make the left systemic arch to the dorsal aorta Right aortic trunk Goes out to the left side and goes to the right systemic arch Right=deoxygenated blood from the body Left= oxygenated blood from the lungs We still have the 3rd arch and the primitive radix Birds and mammals Here we have for the first time, this beautiful double circuit circulation. It is fully adapted to carry blood from the right side to the lungs, from the left side to the body. It divides to a pulmonary trunk, but now there is only one systemic trunk (or aortic trunk). Arches 1,2,5 disarppear. Ventral aorta splits to 2 trunks. Left iv arch (birds): left subclavian artery. Right IV arch (mammals) right subclavian artery. remaining iv arch + aortic trunk: dorsal aorta. pulmonary trunk : joins vi arches which become pulmonary arteries

23. Describe the lymphatic vessels and lymphatic system based on our discussion in class. Lymphatic systemIt is associated with a system of vessels that carries a fluid called Lymph. Lymph is similar to the plasma of the blood and the extracellular fluid we call general tissue fluid and plasma It does not have blood proteins, few blood cells, lymph capillaries, smallest vessels in this system. They collect tissue fluids and are in all the tissues. As blood flows through, the pressure and difference in osmotic concentration, causes fluid to be lost from the blood. Because blood has all of these plasma proteins there is a high colloid osmotic pressure but the of tends to push fluid out. There is a net loss of fluid that needs to be removed and that is happens by the lymph vessels .They are thin walled lymph capillaries with blind ends and they feed into larger lymph vessels. In the digestive tract, there are specialized lymphatic capillaries that are called lacteals because the lymph looks milky and they pick up fats that have been absorbed along the digestive tract. One of the advantages is that the presence of lipids in the blood will increase viscosity in the blood muscles in the walls help to propel lymph.There are valves that ensure that it always move towards the heart and cant flow backwards. They close as lymph tries to flow back. Primary way we get flow to the heart is by skeletal muscle contraction that squeezes the lymph vessels together and cause it to flow upwards, also the general movement of visceral organs

24. Describe the basic plan of the vertebrate kidneys and identify the embryonic tissue layer from which they arise. The basic plan of the vertebrate kidney is to get rid of excess waste, water, and ions. They arise from neprhogenic mesoderm.