The document summarizes the structure and function of blood vessels. It describes three types of blood vessels - arteries, which carry oxygenated blood away from the heart and have thick muscular walls; capillaries, which are thin-walled and allow for nutrient/gas exchange; and veins, which carry deoxygenated blood back to the heart and have thin walls with valves. It also compares blood vessels across species like fish, amphibians, reptiles, birds, and mammals; and notes that in mammals the heart is four-chambered and blood circulation is double and complete through three layers in arteries/veins and a single layer in capillaries.
this ppt gives more clear information about origin of chordata. chordates are those organism which retain notochord in their life history atleast once.
Evolutionary change in heart of vertebrates
Heart is situated ventral to the oseophagus in the pericardial section of the coelom.
Heart is a highly muscular pumping organ that pumps blood into arteries and sucks it back through the veins.
In vertebrates it has undergone transformation by twisting from a straight tube to a complex multi-chambered organ.
. There has been an increase in the number of chambers in heart during evolution of vertebrates.
The heart is covered by a transparent protective covering, called pericardium. It is a single layer in fish.
Within pericardium there is a pericardial fluid, protects the heart from the external injury.
The evolution of the heart is based on the separation of oxygenated blood from deoxygenated blood for efficient oxygen transport.
Central nervous system: The central nervous system consists of the brain and spinal cord. The brain plays a central role in the control of most bodily functions, including awareness, movements, sensations, thoughts, speech, and memory. Some reflex movements can occur via spinal cord pathways without the participation of brain structures. The spinal cord is connected to a section of the brain called the brainstem and runs through the spinal canal.
Peripheral Nervous System: Nerve fibers that exit the brainstem and spinal cord become part of the peripheral nervous system. Cranial nerves exit the brainstem and function as peripheral nervous system mediators of many functions, including eye movements, facial strength and sensation, hearing, and taste.
The autonomic nervous system: The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. This system is the primary mechanism in control of the fight-or-flight response.
The autonomic nervous system comprises two antagonistic sets of nerves, the sympathetic and parasympathetic nervous systems. The hypothalamus is the key brain site for central control of the autonomic nervous system, and the paraventricular nucleus is the key hypothalamic site for this control.
Divisions of Nervous System:
The vertebrate nervous system has three divisions:
(i) A central nervous system comprising the brain and spinal cord. Its function is to receive the stimulus from the receptors and transmit its response to the effectors. Thus, it coordinates all the functions of the body.
(ii) A peripheral nervous system consisting of cranial and spinal nerves arising from the brain and spinal cord respectively. It forms a connecting link between the receptors, central nervous system (CNS) and effectors.
(iii) An autonomic nervous system made of two ganglionated sympathetic nerves, ganglia in the head and viscera, and their connecting nerves. The autonomic nervous system is often regarded as a part of the peripheral nervous system because the two are connected. But all the three divisions of the nervous system are connected intimately both structurally and functionally.
this ppt gives more clear information about origin of chordata. chordates are those organism which retain notochord in their life history atleast once.
Evolutionary change in heart of vertebrates
Heart is situated ventral to the oseophagus in the pericardial section of the coelom.
Heart is a highly muscular pumping organ that pumps blood into arteries and sucks it back through the veins.
In vertebrates it has undergone transformation by twisting from a straight tube to a complex multi-chambered organ.
. There has been an increase in the number of chambers in heart during evolution of vertebrates.
The heart is covered by a transparent protective covering, called pericardium. It is a single layer in fish.
Within pericardium there is a pericardial fluid, protects the heart from the external injury.
The evolution of the heart is based on the separation of oxygenated blood from deoxygenated blood for efficient oxygen transport.
Central nervous system: The central nervous system consists of the brain and spinal cord. The brain plays a central role in the control of most bodily functions, including awareness, movements, sensations, thoughts, speech, and memory. Some reflex movements can occur via spinal cord pathways without the participation of brain structures. The spinal cord is connected to a section of the brain called the brainstem and runs through the spinal canal.
Peripheral Nervous System: Nerve fibers that exit the brainstem and spinal cord become part of the peripheral nervous system. Cranial nerves exit the brainstem and function as peripheral nervous system mediators of many functions, including eye movements, facial strength and sensation, hearing, and taste.
The autonomic nervous system: The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions, such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. This system is the primary mechanism in control of the fight-or-flight response.
The autonomic nervous system comprises two antagonistic sets of nerves, the sympathetic and parasympathetic nervous systems. The hypothalamus is the key brain site for central control of the autonomic nervous system, and the paraventricular nucleus is the key hypothalamic site for this control.
Divisions of Nervous System:
The vertebrate nervous system has three divisions:
(i) A central nervous system comprising the brain and spinal cord. Its function is to receive the stimulus from the receptors and transmit its response to the effectors. Thus, it coordinates all the functions of the body.
(ii) A peripheral nervous system consisting of cranial and spinal nerves arising from the brain and spinal cord respectively. It forms a connecting link between the receptors, central nervous system (CNS) and effectors.
(iii) An autonomic nervous system made of two ganglionated sympathetic nerves, ganglia in the head and viscera, and their connecting nerves. The autonomic nervous system is often regarded as a part of the peripheral nervous system because the two are connected. But all the three divisions of the nervous system are connected intimately both structurally and functionally.
The basic fundamental plan of the aortic arches is similar in different vertebrates during embryonic stages.
But in adult the condition of the arrangement is changed either being lost or modified considerably.
The number of aortic arches is gradually reduced as the scale of evolution of vertebrates is ascended.
The embryonic aortic arches were basically six pairs.
But with progressive evolution , there has been consequent reduction in numbers of aortic arches.
In the basic pattern the major arterial channels consists of
A ventral aorta emerging from the heart and passing forward beneath the pharynx
A dorsal aorta paired above the pharynx and passing caudal above the digestive tract.
Six pairs of aortic arches connecting ventral aorta to with the dorsal aorta.
1st aortic arch= Mandibular aortic arch
2nd Aortic arch= hyoid aortic arch
3rd ,4th ,5th and 6th aortic arches in case of aquatic animal , known as branchial aortic arches.
Introduction
Ostracoderms (shell-skinned) are of several groups of extinct, primitive, jawless fishes that were covered in an armour of bony plates.
They appeared in the Cambrian, about 510 million years ago, and became extinct towards the end of the Devonian, about 377 million years ago. They were quite abundant during the upper Silurian and Devonian periods. Most of fossils of Ostracodermi were preserved in the bottom sediments of freshwater streams.
However, the opinion is sharply divided as to whether their habitat was freshwater or marine.
The first fossil fishes that were discovered were ostracoderms.
The Swiss anatomist Louis Agassiz received some fossils of bony armored fish from Scotland in the 1830s.
The ostracoderms resembled the present day cyclostomes (lampreys and hagfishes) in many respects and together with them constitute a special group of jawless vertebrates, the Agnatha.
Characteristics: They use gills exclusively for respiration but not for feeding . Earlier chordates with gills used them for both respiration and feeding. Ostracoderms had separate pharyngeal gill pouches along the side of the head, which were permanently open with no protective operculum. mostly small to medium-sized fishes, protected by a heavy, bony dermal (derived from skin) armor. bottom-dwellers; filter-feeders or grazers. no paired fins, but many with stabilizing paired flaps on either side of head.
(1) Ostracoderms were the first vertebrates.
(2) They were popularly called armoured fishes.
(4) They lived in freshwater.
(5) They were bottom dwellers.
(6) Their body was fish-like and did not exceed 30 cm in size.
(7) Paired fins were absent.
(8) Median and caudal fins were present.
(9) The caudal fin was of heterocercal type.
(10) The head and thorax were covered by heavy armour of bones. It protected ostracoderms from the giant scorpion like arthropods, eurypterids.
(11) Bony skull was well developed.
(12) Mouth was mostly present on the ventral side.
(13) They were having large number of gill slits.
(14) The nervous system had 10 pairs of cranial nerves.
(15) The head had a pair of lateral eyes, and a median pineal eye.
(16) They were filter feeders, feeding like a vacuum cleaner.
(17) The endoskeleton was either bony or cartilaginous.
ORIGIN OF CHORDATES
Animal kingdom is basically divided into two sub kingdoms:
Non-chordata- including animals without notochord.
Chordata- This comprising animals having notochord or chorda dorsalis.
Chordates were evolved sometime 500 million years ago during Cambrian period (invertebrates were also began to evolve in this period) .
Chamberlain (1900) pointed out that all modern chordates possess glomerular kidneys that are designed to remove excess water from body.
It is believed that Chordates have originated from invertebrates.
It is difficult to determine from which invertebrate group the chordates were developed.
Chordate ancestors were soft bodied animals. Hence they were not preserved as Fossils.
However, early fossils of chordates have all been recovered from marine sediments and even modern protochordates are all marine forms.
Also glomerular kidneys are also found in some marine forms such as myxinoids and sharks. That makes the marine origin of chordates more believable.
Chordates evolved from some deuterostome ancestor (echinoderms, hemichordates, pogonophorans etc.) as they have similarities in embryonic development, type of coelom and larval stages.
Many theories infers origin of chordates, hemichordates and echinoderms from a common ancestor.
Origin of the Lateral Line System
Lateral line is a canal along the side of a fish containing pores that open into tubes supplied with sense organs sensitive to low vibrations.
Robert H. Denison explained the origin of the lateral line system. He explained that early vertebrates had a pore-canal system in the dermis which functioned as a primitive sensory system in detecting water movement.
Through the evidences from fossils, embryology and comparative anatomy, Denison (1966) established that the inner ear is closely related to the lateral line system. He found a distinct relationship between the pore canal system and the lateral line in Osteotraci.
The inner ear and the lateral line are developed from ectodermal thickenings, called dorso-lateral placodes. These have a number of similarities, including receptors with sensory hairs, and are both innervated by fibers in the acoustico-lateral area of the brain.
The pore canal system is present and developed in Osteostraci (ostracoderm).
It is also present in Heterostraci which is another group of ostracoderms and includes early vertebrates such as lungfishes and crossopterygians.
As its presence is extensive, it is reasonable to suggest that the pore canal system was a primitive character in early vertebrates .
In transverse sections also , it is very difficult to differentiate the pore canal system from a lateral line canal.
Structure of the Lateral Line System
Epidermal structures called neuromasts form the peripheral area of the lateral line.
Neuromasts consist of two types of cells, hair cells and supporting cells.
Hair cells have an epidermal origin and each hair cell has one high kynocyle (5-10 μm) and 30 to 150 short stereocilia (2-3 μm).
The number of hair cells in each neuromast depends on its size, and they can range from dozens to thousands.
Hair cells can be oriented in two opposite directions with each hair cell surrounded by supporting cells.
At the basal part of each hair cell, there are synaptic contacts with afferent and efferent nerve fibers. Afferent fibers, transmit signals to the neural centres of the lateral line and expand at the neuromast base. The regulation of hair cells is achieved by the action of efferent fibers.
Stereocilia and kinocilium of hair cells are immersed into a cupula and are located above the surface of the sensory epithelium.
The cupula is created by a gel-like media, which is secreted by non-receptor cells of the neuromast.
The chordates are named for the notochord: a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and also in the adult stage of some chordate species.
It is located between the digestive tube and the nerve cord, providing skeletal support through the length of the body.
In some chordates, the notochord acts as the primary axial support of the body throughout the animal's lifetime.
The vertebrate brain
The vertebrate brain is the main part of the central nervous system. The brain and the spinal cord make up the central nervous system,
In most of the vertebrates the brain is at the front, in the head. It is protected by the skull and close to the main sense organs.
Brains are extremely complex and the part of human and animal body. The brain controls the other organs of the body, either by activating muscles or by causing secretion of chemicals such as hormones and neurotransmitters.
Muscular action allows rapid and coordinated responses to changes in the environment.
The brain of an adult human weights about 1300–1400 grams .
In vertebrates, the spinal cord by itself can cause reflex responses as well as simple movement such as swimming or walking. However, sophisticated control of behaviour requires a centralized brain.
The structure of all vertebrate brains is basically the same.
At the same time, during the course of evolution, the vertebrate brain has undergone changes, and become more effective.
In so-called 'lower' animals, most or all of the brain structure is inherited, and therefore their behaviour is mostly instinctive.
In mammals, and especially in man, the brain is developed further during life by learning. This has the benefit of helping them fit better into their environment. The capacity to learn is seen best in the cerebral cortex.
Three principles
The brain and nervous system is essentially a system which makes connections. It has input from sense organs and output to muscles. It is connected in several ways with the endocrine system, which makes hormones, and the digestive system and sex system. Hormones work slowly, so those changes are gradual.
The brain is a kind of department store. It has, all inter-connected, departments which do different things. They all help each other gather senses.
Much of what the body does is not conscious. Basically, much of the body runs on automatic (breathing, heart beat, hungry, hair growth) adjusted by the autonomic nervous system. The brain, too, does much of its work without a person noticing it. The unconscious mind refers to the brain activities which are hardly ever noticed.
Physiology of Respiration in InvertebratesPRANJAL SHARMA
In physiology, respiration is the movement of oxygen from the outside environment to the cells within tissues, and the removal of carbon dioxide in the opposite direction. In these slides you will get to know about Physiology of Respiration in Invertibrates.
Metabolism: the word to describe the totality of energy consuming, manipulative and storage chemical reactions by organisms.
Second law of thermodynamics dictates that all processes increase amount of entropy in the universe. Thus, a highly ordered entity like a fish can only exist with a constant input of energy that allows it to remain ordered.
Therefore, initial requirement of fish survival is to obtain sufficient energy to offset this universal randomization process by: maintaining ion gradients and renewing proteins (Chabot et al., 2016). “Respiration is nothing but a slow combustion of carbon and hydrogen, similar in all respects to that of a lamp or a lighted candle, and from this point of view, animals which breathe are really combustible substances burning and consuming themselves” (Lavoisier & Laplace, 1783).
All animals must supply their cells with oxygen and rid their body of carbon dioxide.
The physiological process by which an animal exchanges oxygen and carbon dioxide with its environment.Most fish have external gills that are ventilated by a unidirectional flow of water, by pumping or swimming.
Fine sieve structure of gills very efficiently extracts O2 from water.
Efficient O2 uptake is vital to fish because of its low water solubility.
Solubility decreases with increased temperature & salinity!
Also, metabolic rate (demand for O2 ) increases as temperature rises.
‘Branchia’ in greek = ‘gills’
In boney fish (Teleosts):
Gills lie in a branchial cavity covered by the operculum:
Usually two sets of four holobranchs.
Each holobranch consists of two hemibranchs (‘half gill’):
Anterior and posterior
Hemibranchs consist of a row of long filaments (primary lamellae) with semilunar folds (secondary lamellae).
Lamellae or filaments:
Connective tissue scaffold (epithelial cells) framing a vascular network providing blood flow primarily used for gas and ion exchange.Fish employ the countercurrent system to extract O2 from the water.
This system moves water flowing across the gills, in an opposite direction to the blood flow creating the maximum efficiency of gas exchange. Blood flow through lamellae is from posterior to anterior
(back to front).
Water flow over lamellae is from anterior to posterior
(front to back).
Counter-current allows for diffusion from high O2 in water to low O2 in blood across entire length of lamella.Gas gland is location of action in wall of swim bladder (rete mirabile “wonderful net” and surrounding tissues)
Need to pry O2 molecules from Hb molecules in gas gland
Need to accumulate enough O2 (>pO2) in solution in blood plasma to generate a diffusion gradient from distal end of rete mirabile into lumen of swim bladder
Change of pH in blood causes change in bond strength of Hb for O2
Bohr effect--decrease in affinity of Hb for O2 due to decreasing pH or increasing pCO2 affinity: strength of attraction of Hb for O2
Root effect--decrease in capacity of Hb for O2 due to decreasing pH or increasing pCO2
The basic fundamental plan of the aortic arches is similar in different vertebrates during embryonic stages.
But in adult the condition of the arrangement is changed either being lost or modified considerably.
The number of aortic arches is gradually reduced as the scale of evolution of vertebrates is ascended.
The embryonic aortic arches were basically six pairs.
But with progressive evolution , there has been consequent reduction in numbers of aortic arches.
In the basic pattern the major arterial channels consists of
A ventral aorta emerging from the heart and passing forward beneath the pharynx
A dorsal aorta paired above the pharynx and passing caudal above the digestive tract.
Six pairs of aortic arches connecting ventral aorta to with the dorsal aorta.
1st aortic arch= Mandibular aortic arch
2nd Aortic arch= hyoid aortic arch
3rd ,4th ,5th and 6th aortic arches in case of aquatic animal , known as branchial aortic arches.
Introduction
Ostracoderms (shell-skinned) are of several groups of extinct, primitive, jawless fishes that were covered in an armour of bony plates.
They appeared in the Cambrian, about 510 million years ago, and became extinct towards the end of the Devonian, about 377 million years ago. They were quite abundant during the upper Silurian and Devonian periods. Most of fossils of Ostracodermi were preserved in the bottom sediments of freshwater streams.
However, the opinion is sharply divided as to whether their habitat was freshwater or marine.
The first fossil fishes that were discovered were ostracoderms.
The Swiss anatomist Louis Agassiz received some fossils of bony armored fish from Scotland in the 1830s.
The ostracoderms resembled the present day cyclostomes (lampreys and hagfishes) in many respects and together with them constitute a special group of jawless vertebrates, the Agnatha.
Characteristics: They use gills exclusively for respiration but not for feeding . Earlier chordates with gills used them for both respiration and feeding. Ostracoderms had separate pharyngeal gill pouches along the side of the head, which were permanently open with no protective operculum. mostly small to medium-sized fishes, protected by a heavy, bony dermal (derived from skin) armor. bottom-dwellers; filter-feeders or grazers. no paired fins, but many with stabilizing paired flaps on either side of head.
(1) Ostracoderms were the first vertebrates.
(2) They were popularly called armoured fishes.
(4) They lived in freshwater.
(5) They were bottom dwellers.
(6) Their body was fish-like and did not exceed 30 cm in size.
(7) Paired fins were absent.
(8) Median and caudal fins were present.
(9) The caudal fin was of heterocercal type.
(10) The head and thorax were covered by heavy armour of bones. It protected ostracoderms from the giant scorpion like arthropods, eurypterids.
(11) Bony skull was well developed.
(12) Mouth was mostly present on the ventral side.
(13) They were having large number of gill slits.
(14) The nervous system had 10 pairs of cranial nerves.
(15) The head had a pair of lateral eyes, and a median pineal eye.
(16) They were filter feeders, feeding like a vacuum cleaner.
(17) The endoskeleton was either bony or cartilaginous.
ORIGIN OF CHORDATES
Animal kingdom is basically divided into two sub kingdoms:
Non-chordata- including animals without notochord.
Chordata- This comprising animals having notochord or chorda dorsalis.
Chordates were evolved sometime 500 million years ago during Cambrian period (invertebrates were also began to evolve in this period) .
Chamberlain (1900) pointed out that all modern chordates possess glomerular kidneys that are designed to remove excess water from body.
It is believed that Chordates have originated from invertebrates.
It is difficult to determine from which invertebrate group the chordates were developed.
Chordate ancestors were soft bodied animals. Hence they were not preserved as Fossils.
However, early fossils of chordates have all been recovered from marine sediments and even modern protochordates are all marine forms.
Also glomerular kidneys are also found in some marine forms such as myxinoids and sharks. That makes the marine origin of chordates more believable.
Chordates evolved from some deuterostome ancestor (echinoderms, hemichordates, pogonophorans etc.) as they have similarities in embryonic development, type of coelom and larval stages.
Many theories infers origin of chordates, hemichordates and echinoderms from a common ancestor.
Origin of the Lateral Line System
Lateral line is a canal along the side of a fish containing pores that open into tubes supplied with sense organs sensitive to low vibrations.
Robert H. Denison explained the origin of the lateral line system. He explained that early vertebrates had a pore-canal system in the dermis which functioned as a primitive sensory system in detecting water movement.
Through the evidences from fossils, embryology and comparative anatomy, Denison (1966) established that the inner ear is closely related to the lateral line system. He found a distinct relationship between the pore canal system and the lateral line in Osteotraci.
The inner ear and the lateral line are developed from ectodermal thickenings, called dorso-lateral placodes. These have a number of similarities, including receptors with sensory hairs, and are both innervated by fibers in the acoustico-lateral area of the brain.
The pore canal system is present and developed in Osteostraci (ostracoderm).
It is also present in Heterostraci which is another group of ostracoderms and includes early vertebrates such as lungfishes and crossopterygians.
As its presence is extensive, it is reasonable to suggest that the pore canal system was a primitive character in early vertebrates .
In transverse sections also , it is very difficult to differentiate the pore canal system from a lateral line canal.
Structure of the Lateral Line System
Epidermal structures called neuromasts form the peripheral area of the lateral line.
Neuromasts consist of two types of cells, hair cells and supporting cells.
Hair cells have an epidermal origin and each hair cell has one high kynocyle (5-10 μm) and 30 to 150 short stereocilia (2-3 μm).
The number of hair cells in each neuromast depends on its size, and they can range from dozens to thousands.
Hair cells can be oriented in two opposite directions with each hair cell surrounded by supporting cells.
At the basal part of each hair cell, there are synaptic contacts with afferent and efferent nerve fibers. Afferent fibers, transmit signals to the neural centres of the lateral line and expand at the neuromast base. The regulation of hair cells is achieved by the action of efferent fibers.
Stereocilia and kinocilium of hair cells are immersed into a cupula and are located above the surface of the sensory epithelium.
The cupula is created by a gel-like media, which is secreted by non-receptor cells of the neuromast.
The chordates are named for the notochord: a flexible, rod-shaped structure that is found in the embryonic stage of all chordates and also in the adult stage of some chordate species.
It is located between the digestive tube and the nerve cord, providing skeletal support through the length of the body.
In some chordates, the notochord acts as the primary axial support of the body throughout the animal's lifetime.
The vertebrate brain
The vertebrate brain is the main part of the central nervous system. The brain and the spinal cord make up the central nervous system,
In most of the vertebrates the brain is at the front, in the head. It is protected by the skull and close to the main sense organs.
Brains are extremely complex and the part of human and animal body. The brain controls the other organs of the body, either by activating muscles or by causing secretion of chemicals such as hormones and neurotransmitters.
Muscular action allows rapid and coordinated responses to changes in the environment.
The brain of an adult human weights about 1300–1400 grams .
In vertebrates, the spinal cord by itself can cause reflex responses as well as simple movement such as swimming or walking. However, sophisticated control of behaviour requires a centralized brain.
The structure of all vertebrate brains is basically the same.
At the same time, during the course of evolution, the vertebrate brain has undergone changes, and become more effective.
In so-called 'lower' animals, most or all of the brain structure is inherited, and therefore their behaviour is mostly instinctive.
In mammals, and especially in man, the brain is developed further during life by learning. This has the benefit of helping them fit better into their environment. The capacity to learn is seen best in the cerebral cortex.
Three principles
The brain and nervous system is essentially a system which makes connections. It has input from sense organs and output to muscles. It is connected in several ways with the endocrine system, which makes hormones, and the digestive system and sex system. Hormones work slowly, so those changes are gradual.
The brain is a kind of department store. It has, all inter-connected, departments which do different things. They all help each other gather senses.
Much of what the body does is not conscious. Basically, much of the body runs on automatic (breathing, heart beat, hungry, hair growth) adjusted by the autonomic nervous system. The brain, too, does much of its work without a person noticing it. The unconscious mind refers to the brain activities which are hardly ever noticed.
Physiology of Respiration in InvertebratesPRANJAL SHARMA
In physiology, respiration is the movement of oxygen from the outside environment to the cells within tissues, and the removal of carbon dioxide in the opposite direction. In these slides you will get to know about Physiology of Respiration in Invertibrates.
Metabolism: the word to describe the totality of energy consuming, manipulative and storage chemical reactions by organisms.
Second law of thermodynamics dictates that all processes increase amount of entropy in the universe. Thus, a highly ordered entity like a fish can only exist with a constant input of energy that allows it to remain ordered.
Therefore, initial requirement of fish survival is to obtain sufficient energy to offset this universal randomization process by: maintaining ion gradients and renewing proteins (Chabot et al., 2016). “Respiration is nothing but a slow combustion of carbon and hydrogen, similar in all respects to that of a lamp or a lighted candle, and from this point of view, animals which breathe are really combustible substances burning and consuming themselves” (Lavoisier & Laplace, 1783).
All animals must supply their cells with oxygen and rid their body of carbon dioxide.
The physiological process by which an animal exchanges oxygen and carbon dioxide with its environment.Most fish have external gills that are ventilated by a unidirectional flow of water, by pumping or swimming.
Fine sieve structure of gills very efficiently extracts O2 from water.
Efficient O2 uptake is vital to fish because of its low water solubility.
Solubility decreases with increased temperature & salinity!
Also, metabolic rate (demand for O2 ) increases as temperature rises.
‘Branchia’ in greek = ‘gills’
In boney fish (Teleosts):
Gills lie in a branchial cavity covered by the operculum:
Usually two sets of four holobranchs.
Each holobranch consists of two hemibranchs (‘half gill’):
Anterior and posterior
Hemibranchs consist of a row of long filaments (primary lamellae) with semilunar folds (secondary lamellae).
Lamellae or filaments:
Connective tissue scaffold (epithelial cells) framing a vascular network providing blood flow primarily used for gas and ion exchange.Fish employ the countercurrent system to extract O2 from the water.
This system moves water flowing across the gills, in an opposite direction to the blood flow creating the maximum efficiency of gas exchange. Blood flow through lamellae is from posterior to anterior
(back to front).
Water flow over lamellae is from anterior to posterior
(front to back).
Counter-current allows for diffusion from high O2 in water to low O2 in blood across entire length of lamella.Gas gland is location of action in wall of swim bladder (rete mirabile “wonderful net” and surrounding tissues)
Need to pry O2 molecules from Hb molecules in gas gland
Need to accumulate enough O2 (>pO2) in solution in blood plasma to generate a diffusion gradient from distal end of rete mirabile into lumen of swim bladder
Change of pH in blood causes change in bond strength of Hb for O2
Bohr effect--decrease in affinity of Hb for O2 due to decreasing pH or increasing pCO2 affinity: strength of attraction of Hb for O2
Root effect--decrease in capacity of Hb for O2 due to decreasing pH or increasing pCO2
Biology Project [Circulatory System] Vijay Raja Std Vii Navdeep With Soundvijayaswathy
My project was to prepare a presentation on human circulatory system.
This is what it finally looked like .
Hope it comes of some use to you all .
Vijay Raja
Human cardiovascular system, organ system that conveys blood through vessels to and from all parts of the body, carrying nutrients and oxygen to tissues and removing carbon dioxide and other wastes. It is a closed tubular system in which the blood is propelled by a muscular heart. Two circuits, the pulmonary and the systemic, consist of arterial, capillary, and venous components.
The primary function of the heart is to serve as a muscular pump propelling blood into and through vessels to and from all parts of the body. The arteries, which receive this blood at high pressure and velocity and conduct it throughout the body, have thick walls that are composed of elastic fibrous tissue and muscle cells. The arterial tree—the branching system of arteries—terminates in short, narrow, muscular vessels called arterioles, from which blood enters simple endothelial tubes (i.e., tubes formed of endothelial, or lining, cells) known as capillaries. These thin, microscopic capillaries are permeable to vital cellular nutrients and waste products that they receive and distribute. From the capillaries, the blood, now depleted of oxygen and burdened with waste products, moving more slowly and under low pressure, enters small vessels called venules that converge to form veins, ultimately guiding the blood on its way back to the heart.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
2. BLOOD VESSEL:
The blood vessels are
the part of the
circulatory system,
and microcirculation,
that transports blood
throughout the
whole body.
3. TYPES OF BLOOD VESSELS:
There are three major types of blood
vessels. They are as follows:
(1)Arteries: The arteries carry the blood
away from the heart. They are thick
walled.
(2)Capillaries: Capillaries are narrow-
diameter tubes that can fit red blood
cells in single-file lines and are the
sites for the exchange of nutrients,
waste, and oxygen with tissues at the
cellular level.
(3)Veins: The veins carry blood from the
capillaries back toward the heart.
They are thin walled and have valve to
prevent the backflow of blood.
4. STRUCTURE:
• The arteries and veins have three layers. The middle layer is
thicker in the arteries than in the veins.
• The inner layer, Tunica intima is the thinnest layer. It is a layer
of simple squamous epithelium glued by a polysaccharide
intercellular matrix and surrounded by a thin layer of
subendothelial connective tissue.
• The middle layer Tunica media is the thickest layer in arteries. It
consists of elastic fiber, connective tissue, polysaccharide and
elastic lamina. Veins only have internal elastic lamina.
• The outer layer is Tunica adventitia and is the thickest layer in
veins.
• Capillaries consists of little more than a layer of endothelium
and occasional connective tissue.
5.
6. FUNCTION:
A blood vessel’s main function is to transport blood around the
body. Blood vessels also play a role in controlling blood
pressure. Blood vessels are found throughout the body.
7. COMPERATIVE STUDY OF BLOOD VESSELS
Pieces
Arterial System:-
Carry oxygenated Blood.
Have thick and more elastic
made up of Tunica intima,
Tunica Media, Tunica
externa
Efferent Branchial Arteries:-
Collects The blood from
Capillaries of gill lamellae.
Afferent Branchial Arteries
Supply arterial branches to the
anterior and posterior gill
lamellae.
Amphibians
Arteries:-
Carry oxygenated Blood.
Have thick and more elastic
walls
Made up of three concentric
layers ie Tunica intima, Tunica
Media, Tunica externa.
Arterial System can be divided
in to:-
Carotid arch:- Lower jaw and
tongue , Orbit and brain
Systemic arch:- Oesophageal,
occipitovertebral,
subclavian(Forelimbs)
Pulmo-cutaneous arch:- to
lung and skin and buccal cavity
8.
9. Pieces and Amphibia Cont..
Capillaries
Their walls are very thin.
Only tunica intima is present.
Exchange of foods, gases, waste
takes place between blood and
tissue
Veins
Carry deoxygenated blood
Have thin, fibrous and less elastic
walls, than arteries provided with
valves.
Venous system can be divided into
Anterior Cardinal system
Posterior Cardinal System
Hepatic Portal System
Cutaneous System.
Capillaries
Found abundantly in excessive
metabolism sites.
Their walls are very thin.
Only tunica intima is present.
Exchange of foods, gases, waste
takes place between blood and
tissue
Veins
Carry deoxygenated blood
Have thin, fibrous and less elastic
walls, than arteries provided with
valves.
Venous System can be divided into
Pulmonary Veins
Caval veins
Renal portal vein
Hepatic portal
10. Comparative Study of Blood Vessels of
Reptiles and Aves
Arterial system
Three aortic arches (1
pulmonary 2 systemic)
1. One Pulmonary arch
Lies ventrally arises from the
right ventral side of the
ventricle .
Right PA goes to right lung
and left PA goes to left lung.
1. Two Systemic arch
Both the systemic arches
arise directly from the cavum
dorsale of the ventricle
carrying oxygenated blood.
Right and left communicates
each other by Foramen of
Panizzae.
Arterial system
Pulmonary aorta and
systemic arch
1. Pulmonary aorta
Arise from a single
pulmonary aorta which
passes ventral to aortic arch
bifurcates.
Each of these enters into
lung
2. Aortic arch (systemic):-
Arises from left ventricle.
Left aortic arch is absent in
birds
Coronary arteries arise from
right aortic arch
11. Reptile
Some Extensions
Common carotid arteries
Common subclavian artery
Anterior esophageal artery
Dorsal Aorta is formed by
union of right and left
systemic arches , extends
backwards mid dorsal line
beneath the vertebral
column it give rise to: Post
esophageal, Gastric, Coeliac,
hepatic, rectal iliac, caudal
arteries etc
Aves
Simply the arterial
system in Aves is
similar that of reptiles.
13. Reptiles VS Birds
Venous System in Reptiles
1. Pulmonary:- brings oxygenated blood
from lungs to arteries
2. Precaval :- Drains blood from Head,
Neck, Shoulders, Forearm, and Thoracic
wall
Histologically each precaval is formed by
four veins Jugular, Subclavian, Intercostal,
laryngo-tracheal.
3. Postcaval :- collects blood from
posterior body parts i.e. Kidneys Gonads
and Liver
4.Hepatic Portal :- collects blood from
alimentary canals, formed by hepatic
portal vein and Porto- abdominal vein
5. Renal Portal:- Cloacal and rectal veins
meet afferent renal veins
Blood from hindlimb is collected bi
internal and external iliac.
Venous System in Birds
1. Pulmonary veins:- brings
oxygenated blood from lungs to
arteries
2. Precaval veins:- similar in lizard
3. Postcaval veins:-Coccygeo-
Mesentric vein is the
characteristic of Bird. Receive
blood from cloaca and rectum.
4. Hepatic portal:- collects blood
from Rectum, ileum, duodenum
and gizzard.
Coccygeo-Mesentric vein connects the
two portal systems
5. Renal Portal: it is greatly reduced in
the pigeon. Includes two Hypogastric
or renal portal veins.
14. Mammals
• Heart is four chambered. Blood circulation is double, closed
and complete.
• Histologically there are three distinct layers or tunics in
the blood vessels of mammals:-, that form the walls of
blood vessels.
15. Contd.
• Tunica media is composed of smooth muscle,
• Tunica externa is connective tissue (collagen and elastic
fibers).
• The elastic, connective tissue stretches and supports
the blood vessels, while the smooth muscle layer helps
regulate blood flow by altering vascular resistance
through vasoconstriction and vasodilation.
• Unlike veins and arteries, capillaries have only one
tunic; this single layer of cells is the location of
diffusion of oxygen and carbon dioxide between the
endothelial cells and red blood cells, as well as the
exchange site via endocytosis and exocytosis.
