Transcript
Circulatory System
The circulatory system of craniates consists + heart + capillaries or sinusoids+ arteries + blood vascular system + veins or venous sinuses + lymphatic system
The blood is an important agent for circulation:1. Carries oxygen, nutrients, hormones, waste products
and other substances2. Conducts heat
Lymph channels – terminate in venous channels•Collect interstitial fluids and lipids
Arteries Veins or Venous Sinuses
Capillaries or Sinusoids
Function Carry blood away from heart
Blood towards the heart
Site of gas exchange
Structure Muscular and elastic walls can distend
Less muscle and elastic tissue, more fibrous tissue than arteries less distention
Endothelium; some mesenchyme & smooth muscle fibersLumen diameter = size of RBC Precapillary sphincter Capillary shunts
Special terms Smallest: Arterioles (diameter <=0.3mm) – dilate and constrict reflexly thereby assist in regulating blood pressure
Smallest: Venules – provide direct connection to capillariesPortal system
Capillary bed or network – all individual capillaries served by a single arteriole
Covering Loose connective tissue adventitia
Loose connective tissue adventitia
- short section where capillary emerges from arteriole -has smooth muscle fibers that given an adequate neural or hormonal stimulus close off entrance of capillary bed- ex: blushing of skin
- connects arterioles and venules directly - - assure uninterrupted circulation between arterial and venous sides of capillary beds when other capillaries are constricted
-system of veins bounded by capillary beds 1.Renal portal system2.Hepatic portal system 3.Hypophyseal portal system
Structure of Blood Vessels
Renal portal system Hepatic portal system
Hypophyseal portal system
Blood from capillaries of the tail digestive tract, pancreas and spleen
Hypothalamus (contains pituitary regulating hormones)
To capillaries of kidney liver Adenohypophysis
Continue to Heart Heart Heart
Portal Systems
Hepatic portal system
Renal portal system
Arteries Arterioles (Precapillary sphincter) Capillaries (capillary shunts)
Venules
Veins
Pathway of Blood
Development
• Mechanisms of vessel formation– Vascularization
• Process of vessel formation from endothelial precursors with the formation of vessels potentially occurring prior to the onset of blood flow
• May be an inductive interaction with the surrounding tissue (notochord and the axial dorsal aorta)
– Angiogenesis• The remodeling of existing vessels and can occur both
prenatally and postnatally
Angiognesis
Serum-plasma without fibrinogen (clotting substance)
Blood
Hemopoiesis-formation of blood cells-earliest sign: large number of blood islands (produce hemocytoblasts, which are stem cells from which all later blood cells arise)
-blood islands also have extensive network of endothelial-lined spaces. These connect to other blood channels to establish an
early circulatory system
Hemopoiesis (cont.)-descendants of hemocytoblasts form in the tissues within the body
Hemopoietic source Product
Liver, kidney, spleen Craniate RBCs
spleen Craniate WBCs
Bone marrow Amniote RBCs and Granular Leukocytes
Intestinal submucosa Teleost granular leukocytes
Lymphatic tissues lymphoctes
Deteriorating these formed elements in the blood of craniates are done by Macrophages through phagocytosis and amboeboid WBCs in any traumatized tissue of the body
Formed Elements
Formed Elements
Lifespan: 3-4 monthsNumber: 25 trillion Reduces hemoglobin- when oxygen is freed
Formed Elements
Formed Elements
Platelets-participate with fibrinogen in the clotting of blood-tiny fragments of stem cells (megakaryotes) found in the bone marrow
Heart and Its Evolution
• Muscular pump that occupies pericardial cavity
Heart Arteries Walls Endocardium
Myocardium Epicardium
Intima Media Adventitia
Muscle Cardiac Smooth
Heart
• Visceral pericardium – lying on epicardium; = visceral pleuroperitoneum
• Pericardial cavity – space between pericardia
• Coronary arteries and veins
Single Circuit
Blood passes from heart to the gills
From gills directly to all parts of the body
Systemic circuit – oxygenated blood to organs and returns oxygen depleted blood to the heart
Pulmonary circuit – deoxygenated blood from heart to lungs
Returns to the heart
Double CircuitFishes
Craniates who abandoned gills
Hearts of Gill-Breathing Fishes
• 4 chambers – Sinus venosus
• Sinoatrial aperture
– Atrium• Atrioventricular aperture
– Ventricle• Semilunar valves
– Conus arteriosus (truncus arteriosus) or Bulbus arteriosus
Except dipnoans
1. Ventricular contraction – creates suction
2. Filling of sinus venosus
3. Atrium relaxes – blood from sinus venosus valves sinoatrial aperture atrium
Atrial contraction atrioventricular septum valves relaxing ventricle
Conal constriction
Hearts of Dipnoans and Amphibians• Modifications in heart – correlated with aerial respiration
– Separates oxygenated blood returning from swim bladders or lungs from deoxygenated blood from other organs
– Establishment of a partial or complete interatrial septum right (O2 poor) and left atrial (O2 rich) chambers
– Formation of a partial interventricular septum (dipnoans & Siren) or ventricular trabeculae (amphibians)
- Fxn: maintain separation of oxygenated and unoxygenated blood - trabeculae – shelves or ridges projecting from the ventricular wall into the chamber and running mostly cephalo caudad
1. Formation of a spiral valve in the conus arteriosus-valves direct O2 poorblood into aortic arches that lead to gills or
lungs and channelize oxygenated blood into arches that supply other organs 4. Shortened ventral aorta
- Blood moves from conus arteriosus directly to appropriate vessels
Hearts of Amniotes • 2 atria, 2 ventricles
+ 1 ventricular chamber in turtles and squamates
- Sinus venosus in birds and mammals sinoatrial (SA) node
Sinus venosus in crocodiles is partially incorporated to wall of right atrium
Hearts of Amniotes
• Interatrial septum – completely separates right and left atria – Interarterial foramen or foramen ovale –
confluence of right and left atria during embryonic development; closes during birth, becomes fossa ovalis in medial wall of right atrium
• Sinus venosus right atrium • Pulmonary veins left atrium
• One-way valves guard the passageways from atria into ventricles.
• Each valves consist of one or more fibrous flaps or cusps, connected chiefly in mammals by tendonous cords (chordae tendineae) to papillary muscles that project from the ventricular walls
Heart valves
Innervation of the Heart
• Hagfish heart – no external innervation; only modified intrinsic cells that respond to circulatory signals
Innervation of the Heart
• Vertebrate heart – Autogenic – require no external neural stimulus
only to produce a regular beat that can be increased or slowed reflexly by CNS
– Pulsation depends on appropriate concentrations of certain electrolytes (Na, K, Ca ions)
– Purkinje fibers – intrinsic conduction system composed of atypical cardiac muscle that constitute a conduction network with high conductile competence
Innervation of the Heart
ARTERIAL CHANNELS AND THEIR MODIFICATIONS
Circulatory System
ARTERIAL CHANNELSsupply most organs with oxygenated
blood, although they carry deoxygenated blood to respiratory
organs
PRIMITIVE PATTERS OF GNANOSTOMES
VENTRAL AORTA(paired in early embryogenesis) –
emerges from the heart and passes forward beneath the pharynx
DORSAL AORTA(paired above the pharynx only) –
extends caudad in the roof of the coelom
SIX PAIRS OF AORTIC ARCHES – connects the ventral aorta with the dorsal aorta
FIGURE 14.16Page 327
SQUALUSVENTRAL AORTA extends forward under the pharynx and connects with the developing aortic arch (fig. 14.17)FIRST TO DEVELOP aortic arches in mandibular arch
posttrematic arteries → sprout crosstrunks crosstrunks = grows caudad in the holobranch and by further budding establish the last four pretrematic arteries
AORTIC ARCH OF FISHES
AORTIC ARCH FATE
1st pair (before the 6th pair appears)ventral segments – disappears
dorsal segments – efferent spiracular arteries2nd pair first pretrematic arteries
3rd pair posttrematic arteries
4th pair posttrematic arteries
5th pair posttrematic arteries
6th pair posttrematic arteriesFIGURE 14.17
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SQUALUSAortic Arches II to VI becomes occluded at oneSite. (broken lines in fig. 14.17(a)) → Afferent Branchial Arteries – segments ventral
to the occlusion → Efferent Branchial Arteries – dorsal segments
(III to VI)Capillary Beds develops within the ninedemibranchAfferent Brachial Arterioles connect theafferent brachial arteries with the capillaries.Efferent Brachial Arterioles return oxygenatedblood from the capillaries to the pretrematicand posttrematic arteries Δ blood entering an aortic arch from the ventral
aorta must pass through gill capillaries before proceeding to the dorsal aorta
AORTIC ARCH OF FISHES
FIGURE 14.17(a)
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TELEOSTSimilar developmental changes: convert the embryonic aortic arches into afferent and efferent brachialarteriesΔ The specific numberconverted determines thenumber of functional gills.1st and 2nd aortic arches tends to
disappear. (fig. 14.18a)
AORTIC ARCH OF FISHES
FIGURE 14.18(a)
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PROTOPTERUS (fig. 14.18b)3rd and 4th embryonic arches do not
become interrupted by gill capillaries.4th pharyngeal arches bear external gills.DIPNOANS, AMIA, POLYPTERUS6th aortic arch - pulmonary vein sprouts
off the left and right and vascularizes swim bladder
* other archinopterygians – swim bladders are supplied from the dorsal aorta
AORTIC ARCH OF FISHES
FIGURE 14.18(b)Page 329
SUMMARY OF AORTIC ARCH OF FISHES
AORTIC ARCH SQUALUS TELEOST PROTOPTERUS DIPNOANS, AMIA, POLYPTERUS
1st pair (before the 6th pair appears)
ventral segments – disappears
dorsal segments – efferent spiracular
arteries
disappear
2nd pair first pretrematic arteries
disappear
3rd pair posttrematic arteries posttrematic arteries not become interrupted by gill
capillaries
4th pair posttrematic arteries posttrematic arteries - not become interrupted by gill
capillaries- bear external gills
5th pair posttrematic arteries posttrematic arteries
6th pair posttrematic arteries posttrematic arteries Pulmonary Vein
Consists of six pairs ofembryonic aortic arches(fig. 1.6)1st and 2nd – transitoryand regress fairly soon(fig. 14.19 and 14.20)After arches I and IIdisappear: arch III (carotid arch) and thepaired dorsal aortaanterior to arch IIIconstitute the internalcarotid arteries (fig.14.18C, 14.19, 14.20)
AORTIC ARCH OF TETRAPODS
FIGURE 14.19Page 330
FIGURE 14.20Page 331
FIGURE 14.18(c)
Page 329
6th pair – vasculized the lung bud to form PulmonaryArteries (fig. 1.6 and 14.20d)Amniotes with theexception of some limblesssquamates lose the 5th aortic arch during embryonic life. (fig. 14.18f-hand 14.19e-h)Frogs and someSalamanders independentlylose the 5th aortic arches.
AORTIC ARCH OF TETRAPODS
FIGURE 14.18(f-h)Page 329
FIGURE 14.19(e-h)
Page 330
AMPHIBIANSMost terrestrial urodeles retain four pairs of
aortic arches. (fig 14.18c)Perennibrachiate urodeles* 3 aortic arches (5th arch either disappear or
unite in part with the 4th during embryogenesis) (fig.14.18d and 14.21)
* Gill Bypass: Larval afferent and efferent branchial arterioles that carry blood from the aortic arches into the gills and back functions throughout life and a short section of the 3rd, 4th, 5th (fused to 6th in Necturus)→ constricted while the animal is using its gills but when the dissolved oxygen in the pond becomes low enough to cause the animal to gulp air, the gills shrink, and the bypasses carry more blood
* Bulbus Arteriosus – maintains a steady non-pulsating arterial pressure in the gills
AORTIC ARCH OF TETRAPODS
FIGURE 14.18(c-d)Page 329
FIGURE 14.21Page 332
ANURANSRetain four aortic arches (III through VI).• 3rd, 4th, 5th – supply the larval external gills during the five or six days these gills function (after) supplies
internal gills until metamorphosis• 6th – sprouts a pulmonary artery that vascularizes the developing lung bud• Changes (fig 14.18e):
1. Aortic Arch V disappears2. Dorsal aorta between the aortic arches III and IV (ductus caroticus) disappears3. Segment of aortic arch VI dorsal to the pulmonary artery (ductus arteriosus) disappears
Δ Result of changes 1&2: blood entering aortic arch III (carotid arch) can pass only to the head• 3: blood entering arch VI (pulmonary arch) can now pass only to the lungs and skin• Systemic arch (4th) – distribute blood to the rest of the body
AORTIC ARCH OF TETRAPODS
FIGURE 14.18(e)
Page 329
Ventricular Trabeculae – separates oxygenated blood in the left atrium and deoxygenated blood in the right atriumHOW?: expulsion from the ventricle of right atrial blood and by action of the spiral valve in the conus arteriosus Ventricular Systole: (1) the valve is flipped into a position that closes off the entrance to the systemic and carotid arches (diverting oxygenated blood into the common aperture that leads to the two pulmonary arches ( fig 14.12b))(2) back pressure builds up in the pulmonary arteries because of filling of the lung capillaries, spiral valve flips into an alternate position that directs exygenated blood into the systemic and carotid arches
AORTIC ARCH OF TETRAPODS
FIGURE 14.12(b)
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ADULT APODANS• Retain III, IV, VI and the ductus carotices• Ductus arteriosus and ductus caroticus are of
small diameter and carry little blood.
AORTIC ARCH OF TETRAPODS
In adult – exhibits three adultaortic arches – III, IV, base of VINo ductus arteriosus and ductuscaroticus except basal lizards andsometimes limbless squamates.INNOVATION: instead ofaeveloping a spiral valve to shuntfresh and deoxygenated bloodInto appropriate arches, theembryonic ventral aorta splitsinto three separate channels: twoaortic trunks (left and rightsystemic arches) and apulmonary trunk (figs 4.18f, arv,alv, and prv; 14.19e and14.22,2,3,4)
AORTIC ARCH OF NONAVIAN REPTILES
FIGURE 14.18(f)
Page 329
FIGURE 14.19(e)
Page 330
FIGURE 14.22(2,3,4)Page 332
CROCODILES(1) the pulmonary trunk emerges from the rightventricle and leads to the left and rightpulmonary arches (fig 14.19e, vessel in blue) -deoxygenated blood sent to the lungs(2) one aortic trunk emerges from the leftventricle and carries oxygenated blood to theright systemicarch and the carotid arches(fig.14.23)(3) second aortic trunk emerges from the rightventricle and leads to the left systemic arch
* from (1)(2)(3) – one would expect than bloodin the left systemic arch would be low in oxygenbecause it comes from the right ventricle –HOWEVER IT IS NOT THE CASE WHEN THEANIMAL IS BREATHING:
FORAMEN OF PANIZZA
AORTIC ARCH OF NONAVIAN REPTILES
FIGURE 14.19(e)
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FIGURE 14.23Page 332
Foramen of Panizza: an aperture that connects the two aortic trunks at their base
During normal respiration: Left-Right Shunt (assure delivery of oxygenated blood to all parts of the body):- the valve at the exit from the right ventricle into the aortic trunk remains closed - the blood from the right ventricle can pass only to the lungs- some oxygenated blood from the left ventricle is shunted through the foramen of panizza to the left systemic arch
Submerged in water: Right-Left Shunt (diverts considerable blood away from the lungs and into the systemic circulation):- pulmonary arteries constrict reflexly, causing a backup of blood in the right ventricle- the valve between the right ventricle and its aortic trunk is forced to open (fig. 14.23b) - some right-ventricular blood is shunted to the aortic trunk that emerges from the left ventricle
→ utilization of the shunt is facilitated by a mild reduction in the blood pressure within the left ventricle
AORTIC ARCH OF NONAVIAN REPTILES
FIGURE 14.23(a)
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FIGURE 14.23(b)
Page 332
TURTLES AND SQUAMATES- have a cavum venosum at the upper limit of the Interventricular septum Cavum venosum: receives deoxygenated blood from the right atrium and is confluent with both the left and right ventricles (fig 14.24)- How do reptiles avoid mixing of oxygenated and deoxygenated blood in the heart? (1) Ventricular Diastole: blood from the right atrium – venous blood – passes through the cavum venosum and enters the right ventricle (cavum pulmonale)
(2) Ventricular Systole: when cavum venosum discharge the deoxygenated blood into the cavum pulmonale to the lungs
(3) Ventricular Diastole: blood from the left atrium – enters the left ventricle (cavum arteriosum)
* MUSCULAR ACTIVITY: displaces the septal wall, blocking the passageways between the cavum venosum, the right atrium, and the cavum pulmonale and opening the passage between the cavum venosum and cavum arteriosum
BLOOD FLOW: Right atrium → Cavum venosum → Cavum Pulmonale → Pulmonary Artery → Lungs → Pulmonary Veins → Left Artery → Cavum arteriosum → Cavum venosum → Aortic trunk → Left and Right systemic arches
AORTIC ARCH OF NONAVIAN REPTILES
When submerged in water or radiant heat is applied to reptile:- pulmonary arteries are constricted- deoxygenated blood in the cavum venosum is shunted away from the cavum pulmonale and into the left aortic arch* if oxygen is insufficient: additional adaptation provides energy for metabolic needs by glycolysis, an anaerobic process
Basal Lizard – retain 5th aortic arch and ductus caroticus on both sidesLimbless lizard and snakes -left lung atrophies and may lose entireleft sixth aortic arch, retaining only a single pulmonary artery
* snakes – left third aortic arch also disappears* adult snake – retain only the right third, the left and right fourth, ductus caroticus, ventral segment of the right sixth aortic arch to the right pulmonary artery arises
AORTIC ARCH OF NONAVIAN REPTILES
First tetrapods in which there is no opportunity in mixing
oxygenated and deoxygenated blood in the heart afterhatching. (fig. 14.6)
- complete interventricular septum- division of embryonic ventral aorta into two trunks (pulmonary trunk from right ventricle/ single aortic trunk from the left) (fig. 14.19 g and h)
Truncus arteriosus and bulbus cordis – vessel carrying the blood from the heart to the early aortic arches
Pulmonary Trunk – leads to the sixth aortic archesAortic Trunk – leads to the third and 4th aortic archesDuctus Arteriosus – shunts blood away from the lungs
and into the dorsal aortaDorsal Aorta – supplies the embryonic respiratory
membranes with the bloodRight –Left Shunt – divert blood away from the lungs
functions in unhatched chicks and fetal mammals
AORTIC ARCH OF BIRDS & MAMMALS
FIGURE 14.6Page 319
FIGURE 14.19(g-h)Page 330
Part Birds Mammals
1st Aortic Arch
x x
2nd Aortic Arch
x x
3rd Aortic Arch
internal carotid internal carotid
4th Aortic Arch
x- arch of aorta directed
to the right(fig. 14.25)
Base remains- arch of aorta directed to the
left(14.26)
5th Aortic Arch
x x
6th Aortic Arch
Right - xLeft - Pulmonary artery
Right – xLeft - Pulmonary Artery
Ductus Caroticus
x x
Ductus Arteriosus
closes before hatching closes with the first gasp of air into the lungs
Paired embryonic
ventral aorta
left and right common carotid and external
carotid arteries
left and right common carotid and external carotid arteries
AORTIC ARCH OF BIRDS & MAMMALS
FIGURE 14.25Page 334
FIGURE 14.26Page 334
• Respiratory surface develops on pharyngeal derivative – buds off the nearest aortic arch usually vascularize the surface
• Pharyngeal arch develops an external or internal gill – aortic arch in that pharyngeal arch vascularizes that gill
• Pharyngeal floor evaginates to form a lung bud – a sprout from the nearest aortic arch vascularis the bud
• Vascularization of pharyngeal derivatives for the respiration has phylogenetic roots that extend back to the first chordate.
AORTIC ARCH & VON BAER’S LAW
• Paired in the head above the pharynx in embryos and some adult fishes and gill-breathing amphibians
• Remains paired in the head in all adults as the internal carotid arteries
• Unpaired in the trunk where it gives off a series of paired somatic branches to the body wall and appendages and a series of paired and unpaired visceral branches.
• Continues to the tail as caudal artery
DORSAL AORTA
• Subclavian Arteries – enlarges segmental arteries (see figs 14.16 and 14.20)- arise in embryos as branches of the paired or unpaired dorsal aortas or from the third aortic archs (somebirds) or fourth aortic arches (some mammals) close to the aorta
- transverse the axilla = axillary artery- Parallels the humerus – brachial artery -Divides in the forearm = ulnar and radial arteries
• Vertebral Artery – passes cephalad in the beck to contribute blood to the curcle of willis (fig. 16.27) - not well developed in birds and some reptile
• Vertebromuscular branches – dorsally directed and branches to the epaxial muscle, skin and vertebral column
• Parietal Branches – encircle the body wall to the midventral line1. Intercostal branches – in long ribs2. Sacral – in Sacral Vertebrae3. Lumbar – in Lumbar Vertebrae
• Iliac- segmental arteries that supply the pelvic fins or limbs1. Femoral – in the thigh2. Popliteal – in the knee3. Tibial – in the shank
• *Anatomose (unite end to end) – ensure that if one of the anastomosing vessels supplying a region becomes occluded, the vessel approaching from the opposite direction will fill the affected arterial tree beyond the occlusion
SOMATIC BRANCHES
A. Series of unpaired visceral branches (splanchnic vessels) pass via dorsal mesenteries to the unpaired viscera, chiefly digestive organs suspended in the coelom
• Necturus – most number of vessels• Celiac, Cranial (Superior) mesenteric and caudal (inferior) mesenteric – as few as 3 may occur
in mammals, birds, Squalus• Anatomoses between two successive visceral branches occur along the entire length of the
gut• Anatomosing Visceral Branches in Mammals:
1. cranial (superior) Pancreaticoduodenal branch of the celiac – caudal (inferior) Pancreaticoduodenal branch of the celiac mesentery2. middle colic branch of the cranial mesenteric – left colic branch of the caudal mesenteric3. cranial rectal branch of the caudal mesenteric – middle rectal branch of the internal iliac* common in greater and lesses curvatures of the stomach
B. Paired Visceral Branches – include arteries to the urinary bladder, reproductive tract, gonads, kidneys and adrenals* series of gonadal and renal arteries occur in basal craniates, several pairs in reptiles and usually a single pair in mammals
VISCERAL BRANCHES
Embryonic dorsal aorta of amniotes ends at the level of the future hind limbs by bifurcation into the left and right allantoic (umbilical) arteries
Internal Iliacs sprout off the umbilical arteries as limbs develop, and as the umbilicals become branches of the external and internal iliacs
ALLANTOIC ARTERIES OF AMNIOTES
Vasa vasorum – vessels of the vessels, found in the walls of arteries and veins.
Coronary arteries and veins – vessels in the heart.(in urodels, the coronary supply consists of many small arteries
Origin:Elasmobranch- from hypobranchial arteries around the gill chambersFrogs – carotid archReptiles – from aortic trunk and brachiocephalicMammals- from the base of the ascending aorta
CORONARY ARTERIES
-‘wonderful networks’-segments of arteries
that are highly tortuous
Examples:-glomeruli -arterial networks in the
pseudobranch of sharks
RETIA MIRABILIA
Cetacians and pinnipeds– Location: trunk and within bony vertebral
canal that houses the spinal cord. They are drained by arteries that are en route to the brain
– Function: constitute a reservoir of RBCs that were oxygenated before a dive, they supply oxygen to the brain when submerged.
RETIA MIRABILIA: FUNC DEPENDS ON LOCATION
Birds that wade in icy waters, polar bears and arctic seals– Location: thigh (retia having arteries and veins side by
side)– Function: countercurrent results in the transfer of
heat
Fishes – Location: swim bladders (retia are called red gland)– Function: provide countercurrents that help maintain
an appropriate level of gaseous oxygen in the bladder
RETIA MIRABILIA: FUNC DEPENDS ON LOCATION
Mammals– Location: testes in
scrotal sacs have a rete, pampiniform plexus, in each inguinal canal
– Function: heat is transferred from spermatic artery to spermatic vein, assuring that the temperature within the scrotal sacs is lower than the body temperature, a necessity for the viability of sperm in those species.
RETIA MIRABILIA: FUNC DEPENDS ON LOCATION
VENOUS CHANNELS AND THEIR MODIFICATIONS
GENERALIZED VENOUS SYSTEM– Cardinals [ant, pos, common cardinals]– Renal portal– Lateral abdominal– Hepatic portal– Hepatic sinuses– Coronary veins
Lungs and tetrapods– Pulmonary stream– Postcava from the kidneys – -drains the whole body
BASIC PATTERN: SHARKS
CCardinal streamsC1. Cardinal veins
- Where blood [except that from the digestive organs] enter to the sinus venosus that which receives blood returning to the heart
- Interior cardinal (precardinal) veins- Blood from the head other than the lower jaw- Empties into the common cardinal
1. E Embryonic Posterior cardinal (postcardinal) vein- Continuous with the caudal vein- Receives renal veins as they pass through the kidneys - Empty into the common common cardinals- Posterior cardinal sinuses
Renal Portal System• Caudal vein continues forward beneath the
gut as a subintestinal vein• When the old postcardinals are lost, blood
from the tail enter the peritubular capillaries
BASIC PATTERN: SHARKS
Lateral Abdominal Stream• Lateral abdominal vein
– from the pelvic and receives an iliac vein– Receives a brachial vein at the pectoral level
before entering the common cardinals– Subclavian vein – between the brachial and the
common cardinals– Cloacal vein – metameric series of parietal veins
from the lateral body wall
BASIC PATTERN: SHARKS
Hepatic Portal Stream and Hepatic Sinuses• Omphalomesenteric (vitelline) veins
– One of the first vessels to appear in any craniates embryo– Yolk sac to heart– Breaks into sinusoidal channels due to the enlarging liver during
development– The vitelline vein from caudal to the liver disappears, while another
associates with the subintestinal vein to become the hepatic portal system
• Subintestinal vein– Joins the vitelline vains and drains the digestive organs
• Hepatic system– two v.veins between the liver and the sinus venosus
BASIC PATTERN: SHARKS
OTHER FISHESLiving agnathans
No renal portal sysNo left common cardinal
Ray-finned fishes
Most have no abdominalsPelvic fins: postcardinalsBlood from swim bladdershepatic/hepatic portal/postcardinal/commoncardinal
dipnoan Pelvic fins: unpaired ventral abdominal emptying into sinus venosusSwim bladders: left atrium
CORONARY VEINS SINUS VENOSUS
TETRAPODS• Embryonic venous channels is the same as that of the sharks
Cardinal Veins and the Precavae– Post cardinals, precardinals, common cardinalsPOSTCARDINALS:
Urodeles - Persist bet caudal and common cardinalsAnurans - Anterior to kidneys disappears
- Connection with the caudal is lostAmniotes Anterior to kidneys disappears in embryonic stage due to
POSTCAVA developmentmammals Ant. of the RIGHT postcardinal persist –AZYGOS
LEFT: HEMIAZYGOS Azygos old right common cardinals precava]
o Receives shunts from the Hemiazygos Both drain intercostals spaces
Amniotes:common cardinals
Precavae
Anterior cardinals
Internal Jugular veins
cats and humans lose most of the left precavao BRACHIOCEPHALIC VEIN, a
transverse vessel drains the left side of the head left anterior limb to the right precava
o Coronary sinus – remnant of the left precava
- On the surface of the <3 that receives coronary veins then empties into the right atrium
o Superior vena cava – right precava precava of nonavian reptiles: sinus venosus birds and humans: right atrium
TETRAPODS
Postcava– subcardinal venous plexus – receives renal veins from
kidneys– postcava – a subcardinal that predominates. Grows into
the mesentery in which is the liver is developing, becomes associated with hepatic sinuses
» kidneys to heart via hepatic sinuses• tetrapods:
– hepatic sinuses fuse forming a median vessel that becomes part of the postcava
– mammals: caudal (inferior) vena cava– crocodilians: blood from the hindlimb passes directly to the postcava
bypassing the kidneys– birds: all blood directly to the postcava
TETRAPODS
AAbdominal Stream1.body wall at the site for future hindlimbs2.cepahalad to the lateral body wall3.receives veins from the developing forelimbs4.common cardinals or sinus venosus
TETRAPODS
TETRAPODSAmphibian Ventral abdominal vein – connects with the venous channels in the falciform ligament
connecting liver to the body wall-one of these channels enlarges making all the blood form the ventral abdominal pass through the falciform ligament to the liverportal stream- between the capillaries of the developing hind limb and that of the liver-due to the disappearance of the segments of the lateral abdomninal vein anterior to the liver-aids in the draining of the digestive organs and spleen
Non-avian reptiles
Lateral abdominals do not unite Uses the falciform ligament as a bridge from the coelom to the liver capillaries Loses connection with the commons (2) allantoic veins –temporary tributaries as the abdominals pass thru the ventral body wall -regress when the allantois is lost prior to hatching
Birds None of the embryonic abdominal stream is seenMammals - Fetal life only
-umbilical [allantoic] vein- all that is left of the abdominalsNo connection with the drainage of the hindlimbsGrows out the umbilical cord and vascularizes the placentaUnite to form a single umbilical vein-functions only to drain the placentaRound ligament of the liverDuctus venosus – eroded by umbilical veinAfter birth becomes the ligamentum venosum
Renal Portal systemAmphibians External [transverse] iliac vein – blood
from hindlimbs to renal port-alternate route to heart- seen also in REPTILES
SnakesCrocodilians
Rps is seen as primitive relationshipSome blood from hindlimbs bypass the kidneys
Birds Hindlimb blood bypass the kidneysTherian mammals
disappears
TETRAPODS
HHepatic Portal System Similar in all craniates Stomach, pancreas, intestines spleen Terminates at the capillaries of the liver Tributaries: abdominal stream [from amphibians
up]
: veins from the swim bladders [bony fishes
TETRAPODS
Coronary veins
TETRAPODS
Amphibians
Frogs:
No definitive coronary system
One c.v enters the left precava,the other empties into the ventral abdominal
Reptiles Coronary veins coronary sinus or directly into the right atriumCoronary sinus lies at the coronary sulcus [between left atrium and ventricle]
Mammals
CIRCULATION IN THE MAMMALIAN FETUS, AND
CHANGES AT BIRTH
Caudal end of dorsal aorta
Umbilical arteries
Umbilical cord
Placenta
Umbilical Vein
Ductus Venosus Liver
Postcava
Right atrium
Interarterial foramen
Left atrium
Left ventricle
Systemic arch
Major venous channels
Right ventricle
Pulmonary Trunk
Lungs
Fetal Adult
foramen ovale fossa ovalis
ductus arteriosus ligamentum arteriosum
extra-hepatic portion of the fetal left umbilical vein
ligamentum teres hepatis (the "round ligament of the liver")
intra-hepatic portion of the fetal left umbilical vein (the ductus venosus) ligamentum venosum
proximal portions of the fetal left and right umbilical arteries
umbilical branches of the internal iliac arteries
distal portions of the fetal left and right umbilical arteries medial umbilical ligaments (urachus)
MAJOR CIRCULATORY CHANGES WHICH ADAPT THE ORGANISM FOR PULMONARY RESPIRATION
The ductus arteriosus closes as a result of nerve impulses passing to its muscular wall.
The interarterial valve is pressed against the interarterial foramen by the sudden increase in pressure in the left atrium that results from the greatly increased volume of blood entering from the lungs.
The umbilical arteries and vein are severed at the umbilicus. Eventually, the umbilical arteries from bladder to navel are converted into lateral umbilical ligaments.
No blood flows through the umbilical vein since source has been cut off. This becomes the round ligament of the liver and the it becomes the ligamentum venosum.
Failure of the foramen ovale to close or of the ductus arteriosus to constrict results in….
CYANOSIS- Blueness of the skin, lips and nail bed in humans
SYSTEMATIC SUMMARY OF RESPIRATION AND CIRCULATION
Amphioxus- transverse muscle in the artrial wall provides a “cough” reflex to dislodge grains and of sand
Gnathostomes- possesses a complex jointed pharyngeal skeleton requiring both inspiratory and expiratory muscles to pump water over the gillsOsteichthyans-air sac- buccopharyngeal muscles used to pump water over the gills are also used to pump a pulse of air into an air sac
See fig. 14.40
Gill – breathing fishes can resort to pulse pumping when challenged by low-oxygen partial pressures.
A species may shift strategies during its life history ( a gill-breathing larva shifting to pulse pumping at metamorphosis).
Any shift to aspiration mode would potentially conserve energy.
Aspiration breathing is seen in all amniotes.
Fossil rhipidistian fishes with lungs were incapable of pulse pumping due to their heavy overlapping ribs and scales.
The large body size and ribs of early tetrapods preclude pulse pumping.
LYMPHATIC SYSTEM
The LYMPHATIC SYSTEM consists of…
1. thin-walled LYMPH CHANNELS
2. LYMPH (fluid)3. LYMPH HEARTS4. LYMPH NODES (birds
and mammals)
5. solitary or aggregated masses
of LYMPH NODULESex. SPLEEN
The system begins in LYMPH CAPILLARIES
or in LYMPH SINUSOIDS.
Fluid empties to a vein.
Valves at these exits prevent the influx of venous blood into the lymph channels.
Capillaries and sinusoids penetrate most of the soft tissues of the body other than the liver and the nervous system. They also collect interstitial fluids.
A lymphatic network consisting of long, narrow, discrete tubular vessels with a modicum of smooth muscle in the walls is found only in birds and mammals.
LACTEALS- lymphatics in intestinal
villi- CHYLE – lymph found
in these vessels; milky appearance
HEMOLYMPH- lymphatics which
contain red blood cells- Living agnathans,
cartilaginous fishes and humans
Lymph channels that drain the body wall, limbs, and tail of craniates empty into nearby veins at the base of the tail, trunk and neck.
Lymph channels draining viscera are often paired in most craniates but in mammals, a single thoracic duct commences in a large abdominal lymph sinus, the cisterna chyli and empties into a branchicephalic of left subclavian vein, or into external or internal jugular veins.
ANURANS-Have numerous sinusoids which form huge lymph reservoirs separated by connective tissue septa that attaches the skin to the underlying muscles
Subcutaneous lymph sinuses – buffers the underlying muscles from the drying effect of air
FACTORS THAT CONTROL THE FLOW OF LYMPH
Lymph hearts at advantageous locations along lymph pathways in fishes, amphibians and reptiles (except postembryonic birds).
Frogs: 2 pairs of lymph heartsUrodeles: 16 pairsCaecilians: 100 pairs
Amphibians have more tissue fluids to manipulate than other craniates so their lymph hearts move a proportionately larger volume of fluid than the hearts of other craniates.
Semilunar valves at the exit of the hearts prevent backflow.
Lymph hearts are not present in birds after hatching but embryonic birds have them.
None has been described in humans.
CRANIATE LYMPH FLOW is maintained…
….by activity of the skeletal muscles as they contract and relax
….by movements of the viscera
….by rhythmical changes in intrathoracic pressure that results from breathing
LYMPH NODES are masses of hemopoietic tissue interposed along the course of lymph channels of birds and mammals.
They are the “swollen glands” you feel in the neck, axilla and groin in humans when there is inflammation in areas drained.
The endothelium of the sinusoidal passageways include phagocytes that ingest bacteria and other particles.
The nodes are the 2nd line of defense against bacterial infections acquired through the skin, the first line being granulocytes that assemble at the invaded area.
LYMPHOID MASSES
Spleen
Thymus(absent in hagfishes)
Tonsils (in humans)
Peyer’s Patches (in amniotes)
Bursa of fabricius (in young birds)
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