Animal form and function- 2 Flashcards
Why doesn’t clotting occur in the undamaged blood vessels?
because the lining of the vessels is very smooth and does not promote platelet aggregation or cell rupture.
Also some substances such as Heparin prevent clotting.
Heparin prevent the conversion of prothrombin into thrombin and fibrinogen to fi brin and is widely used clinically as an anticoagulant.
What is clinically used as an anticoagulant?
Heparin
What is vital during the blood transfusion?
Receiving of blood that is compatible with its own
Therefore prior to transfusion cross-matching is still required to ensure that there is no reaction between donor and recipient blood.
When the blood transfusion is incompatible, what happens in the CVS?
a type of immune response occurs
This is because the donor’s red cell membranes possess glycoprotein which act as antigens and react with antibodies (agglutinin) in the recipient’s plasma.
The result is that the donor’s cells are agglutinated
What organism is known as the universal recipient?
AB blood group
What blood group is known as the universal donor?
O blood group
So these individuals having blood group O can donate blood to the persons with any blood group
Why is the blood group O is known as the universal donor?
Individual with blood group O has neither antigen A nor antigen B on their plasma membrane of red blood cells.
But they do have antibodies (anti–A and anti-B) in their plasma
In ABO blood group system, what are the four blood groups?
A
B
AB
O
What are the antigens the individuals have on the surface of their RBC?
Rhesus factor
aggulitinogen
What are the people having the rhesus factor on their RBC called?
Rh+
What are the people that do not have the rhesus factor on the surface of their RBC called?
Rh-
What individuals have anti rhesus antibodies in their plasma?
Rh- individuals
How does Rh antibodies form in Rh- individuals?
if Rh + blood enters a Rh- negative individual the recipient responds by manufacturing Rh antibodies in
the blood plasma.
What happens when a Rh- mother bears a Rh+ child?
When a Rh- mother bears a Rhesus positive (Rh+) child during delivery few Rh+ red blood cells of the fetus may enter the mother’s circulation and cause the mother to produce Rh antibodies in her plasma.
What happens when a Rh- mom is pregnant for the second time with a Rh+ child?
If the mother is pregnant for the second time with a Rhesus positive fetus, the Rh antibodies developed in her plasma in response
to the first child’s red blood sells can pass across the placenta to the fetus and destroy fetal red cells.
Normally Rh antibodies are not formed in large enough quantities in the mother’s plasma to affect the first born child. However subsequent Rh+ children can suffer destruction of their red blood cells.
Why are respiratory structures needed in animals?
*Respiratory gas exchange (uptake of oxygen into the body and release of carbon dioxide into the external environment) occurs by diffusion. In simple animals e.g. cnidarians and fl at worms every cell in the body is close enough to the external environment so that gas exchange can occur directly between all cells and the environment. Diffusion through body surface is adequate as these animals have a simple body form and low energy requirement.
*In large animals, body complexity and energy requirement is high and the bulk of the cells in the body lack immediate access to the external environment. Hence, gas exchange through the body surface is not adequate to full fill their energy requirements.
As a result, specialized surfaces referred to as respiratory surfaces have evolved where gaseous exchange occurs.
Why are respiratory structures needed in animals?
*Respiratory gas exchange (uptake of oxygen into the body and release of carbon dioxide into the external environment) occurs by diffusion. In simple animals e.g. cnidarians and fl at worms every cell in the body is close enough to the external environment so that gas exchange can occur directly between all cells and the environment. Diffusion through body surface is adequate as these animals have a simple body form and low energy requirement.
*In large animals, body complexity and energy requirement is high and the bulk of the cells in the body lack immediate access to the external environment. Hence, gas exchange through the body surface is not adequate to full fill their energy requirements.
As a result, specialized surfaces referred to as respiratory surfaces have evolved where gaseous exchange occurs.
What happens with the increase of size and complexity of animals?
the surface area to volume ratio (A/V) of animals decreases
Why is a large surface area needed in complex (with high body size) organisms for efficient gas exchange?
A large surface area is required for efficient gas exchange.
Thus diverse respiratory structures with large surface area with folding and branching has evolved for efficient gas exchange.
What are the examples of respiratory structures?
Gills
Trachea
lungs
Why are external projections such as gills evolved in the aquatic organisms?
for efficient extraction of dissolved oxygen from water
Why are surface invaginations like trachea and lungs were evolved in terrestrial animals?
for efficient extraction of oxygen from the atmosphere
What organisms have a body surface as a respiratory structure?
Cnidarians
Flat worms
Earth worms
What organisms use external gills as a respiratory surface?
marine annelids
What organisms use internal gills as a respiratory surface?
Fish
shrimp
prawns
What organisms use tracheal systems as the respiratory surface?
Insects
What organisms use lungs as the respiratory surface?
Mammals (Human)
Reptiles
Birds. (MBR)
What organisms use skin as the respiratory surface?
Amphibians
What organisms use book lungs as the respiratory surface?
Spiders
Scorpions
What does the human respiratory system include?
Nostrils
nasal cavity
pharynx
larynx
a series of branching ducts starting from the trachea
two bronchi one leading to each lung and smaller bronchioles,
air sacs called alveoli
Where are the alveoli and the bronchioles contained within?
paired, cone-shaped lungs located in the thoracic cavity
What lung is larger, left or right?
Right,
This is because the apex of the heart is slightly left to the median plane. Thus, the left lung is smaller
How many lobes does the right and left lung has?
Right lung- 3 lobes
left lung- 2 lobes
What is each lung surrounded by?
by two membranes.
The inner membrane, called the visceral pleura adheres to the outer surface of the lungs,
outer membrane called the parietal pleura adheres to the wall of the thoracic cavity
Between visceral and the parietal pleura, what can be seen?
thin, fluid filled space
What is the passage of air in the respiratory system?
nostrils ===> pharynx ===> larynx ===> trachea ===> bronchi ===> bronchioles
What is the common passage for both air and food?
Pharynx (air and the food passage cross each other)
What happens to the air of the nasal cavity?
In the nasal cavity air is filtered by hairs and is warmed and humidified as it travels through spaces in the nasal cavity.
What can be found in the larynx?
vocal cords which are made up of largely elastic fibers
What can be found in the larynx?
vocal cords which are made up of largely elastic fibers
How does vocal cords produce sound?
when expired air rushes across the stretched or tensed vocal cords, causing them to vibrate.
What does the epithelium found in the major respiratory tract contain?
cilia
thin film of mucus
What is the function of mucus in the respiratory systems’ tract?
The mucus helps trap the dust and other particulate contaminants in the inhaled air
What happens when the cilia beats in the respiratory tract?
Then the beating of cilia moves this mucus upwards towards the pharynx where it is swallowed into the esophagus. This process is referred to as the “mucus escalator”.
What is the function of mucus escalator?
It helps clean the respiratory system.
What are the features of alveoli?
*The lungs contain millions of alveoli. This allows a large surface area for gas exchange.
*Each alveolus is also surrounded by a network of capillaries. Oxygen in the air that enters the alveoli dissolves in the moist film and rapidly diffuse across the thin epithelium into the capillaries. Meanwhile a net diffusion of carbon dioxide occurs from the capillaries into the alveoli.
*Since there are no cilia in the alveoli, there are white blood cells in the alveoli to engulf foreign particles.
*Alveoli are also coated with a surfactant that reduces the surface tension thereby preventing the collapse of alveoli due to high
surface tension.
How do the alveoli prevent the collapse due to high surface tension?
Alveoli are also coated with a surfactant that reduces the surface tension thereby preventing the collapse of alveoli due to high
surface tension.
How do the alveoli prevent the collapse due to high surface tension?
Alveoli are also coated with a surfactant that reduces the surface tension thereby preventing the collapse of alveoli due to high
surface tension.
Why is ventilation of lungs necessary?
Ventilation of the lungs is necessary to maintain high oxygen and low carbon dioxide concentrations in the alveoli or the gas exchange surface.
How is lung ventilation accomplished?
by breathing, which is the alternating movement of air into (inhalation) and out of (exhalation) the lungs.
What type of breathing do humans employ?
Negative pressure breathing
Are the below processes of breathing active or passive?
Inhalation
Exhalation
Inhalation- active process
Exhalation- passive process
What are the events taking place during the process of inhalation?
*Contraction of rib muscles or intercoastal muscles and the diaphragm which is a sheet of skeletal muscle that forms the bottom of the thoracic cavity leads to the expansion of the thoracic cavity.
• The visceral and parietal pleurae surrounding the lung stick together due to the surface tension of the fluid between these two membranes.
*This allows the two membranes to slide smoothly past each other. Hence, as the volume of the
thoracic cavity increases, the lung volume increases as well.
• As a result, the pressure within the lungs decrease relative to the outside air.
• This creates a pressure gradient between the atmosphere and the lungs.
• Thus, air flows from a high pressure gradient in the atmosphere to a lower pressure gradient in the lungs.
What events take place during exhalation?
*The rib muscles and the diaphragm relax.
*This cause the volume of the thoracic cavity to reduce.
• As a result, the pressure inside the lungs increase in relation to the air outside.
*This pressure forces air to move out of the lungs through the respiratory tubes
into the atmosphere.
When a man is at rest, what is enough for breathing process?
When a man is at rest contraction of rib muscles and contraction of diaphragm
What are the additional muscles that aid in the breathing process?
muscles of the neck, back and chest.
What do the muscles of the chest, back and neck increase?
These muscles further help to increase the volume of the thoracic cavity by raising the rib cage. e.g.
during exercise
Why do the lungs act as efficient respiratory surfaces?
• Alveoli create a large surface area for gas exchange.
• Alveoli and capillary walls are both lined by simple squamous epithelia which
reduce the distance the gasses need to travel by diffusion.
• The alveoli surface is moist to dissolve respiratory gasses for diffusion.
• Alveoli are highly vascularized which enables the maintenance of a steep
diffusion gradient of respiratory gasses
What is the difference between internal and external breathing?
It requires transport of O2 from the lungs to the blood and movement of CO2 from the blood
(referred to as external respiration) and movement of O2 from blood to the tissues and
CO2 from tissues to the blood (referred to as internal respiration).
What does the diffusion of Oxygen and CO2 require during the respiration?
It requires partial pressure gradients between the alveolar air in
the lungs and blood (during external respiration) and blood and tissues (during internal
respiration).
What takes place during the inhalation process? (at internal respiration level)
During inhalation, fresh air mixes with the stale air in the lungs.
This mixture in the lungs has a higher partial pressure of oxygen (PO2) and a lower partial pressure
of carbon dioxide (PCO2) than the blood in the alveolar capillaries.
There is thus a concentration gradient favoring the diffusion of these two gases in opposite directions.
Net diffusion of O2 takes place from the air in the alveoli to the blood and net diffusion of CO2 takes place from the blood into the alveoli.
What happens the O2 diffuses into the blood capillaries?
When O2 molecules diffuses into blood capillaries they bind to heamoglobin in the red blood cells. Four molecules of O2 bind reversibly with one molecule of haemoglobin and form oxyhemoglobin
What happens when blood leaves the alveolar capillaries the oxygen and carbon dioxide partial pressures?
They will be in equilibrium
What happens when blood leaves the alveolar capillaries the oxygen and carbon dioxide partial pressures?
They will be in equilibrium
What happens during the loading and unloading O2 and CO2?
- Blood reaching the tissues in the systemic capillaries have a higher PO2 and a lower PCO2 than in the tissues.
- These partial pressure gradients result in the net diffusion from the blood stream into the tissue and CO2 diffusion from the cells into the blood stream across the extracellular fluid/interstitial fluid.
- This is called unloading of O2 and loading of CO2
- Then the blood returns to heart and pumped to lungs again.
What is breathing regulated by?
Involuntary mechanisms
What do the involuntary mechanisms of breathing help coordinate?
help coordinate gas exchange with blood circulation and metabolic demands
What is the main breathing regulator center in the brain?
Medulla oblongata, at the base of the brain
Where are the pair of breathing control centers found in homeostatic control of breathing?
There are a pair of breathing control centers found in medulla and they are responsible for regulating the breathing rhythm.
What process control homeostatic control of breathing?
A negative-feedback mechanism
What do the sensors found in the lungs detect?
Sensors which detect stretching of the lung tissues are found in the lungs.
What do the sensors in the lungs do in inhalation?
During inhalation, these sensors send nerve impulses to the neurons that act as control
circuits in the medulla and further inhalation is inhibited and this prevents the
lungs from over expanding.
To regulate breathing, what does the medulla depends on?
pH changes in tissue fluids.
What is the indicator for CO2 concentration?
The pH of tissue fluid
What happens in blood when the CO2 concentration increases?
when metabolic activities increase, the concentration of CO2 in the blood increases.
Because CO2 diffuse into the cerebrospinal fluid, this results in an increase of CO2 concentration in the cerebrospinal fluid as well.
There CO2 reacts with water and form carbonic acid (H2CO3). H2CO3 dissociate into HCO3-
and H+
Hence, a high CO2 concentration results in an increase in H+ concentration, thereby a lower pH.
How is the low Ph is detected in the blood?
This pH change is detected by the sensors in the medulla and in major blood
vessels called arteries and aorta.
How is the low blood Ph controlled?
Sensors in the medulla and major blood vessels detect this decrease in pH.
In response, the control circuits in medulla increase the depth and rate of breathing until the excess CO2 is removed in exhaled air and the pH of blood comes to its normal value which is 7.4
How is the Ph change detected by the blood?
Sensors in the medulla and major blood vessels detect this decrease in pH. In
response, the control circuits in medulla increase the depth and rate of breathing
until the excess CO2 is removed in exhaled air and the pH of blood comes to its
normal value which is 7.4
Describe the influence of Oxygen in the breathing control centers
The O2 level has little influences on the breathing control centers. But, when O2
concentration becomes very low, O2 sensors found in the aorta and the carotid
arteries send impulses to the medulla to increase the breathing rate
What are the additional systems in which breathing modulated by?
The regulation of breathing is also modulated by additional neural circuits in the
pons, a part of the brain stem found above the medulla.
Why is cigarette smoke bad for the body?
Cigarette smoke harms nearly every organ in the body including the organs of the respiratory system and increase the risk of illness, disability and death.
What is an addictive drug in the smoke?
Nicotine
What are the adversities of nicotine?
It temporarily increases the rate of heart beat
constriction of peripheral blood vessels causing a temporary increase in blood pressure.
What does cigarette smoke stimulate?
- The secretion of mucus by the goblet cells
- Inhibits the action of cilia in the respiratory tract
What does cigarette smoke cause?
Causing accumulation of mucus in bronchioles and blocking them
Leading to bronchial inflammation or bronchitis.
As a result, breathing may become difficult.
What are the adversities of HCN?
- It stops the cilia from working properly.
- Due to loss of action of cilia, dust and other particulate matter get collected in the lung, resulting in an increase in phagocytic cells in the lung tissue.
- Due to release of large amounts of lytic enzymes by these cells, the alveolar tissue is destroyed thus reducing the effective area available for gas exchange.
What does CO in tobacco smoke do?
Smoke is absorbed into the blood and is able to bind to hemoglobin better than oxygen and combines irreversibly
with hemoglobin.
Thus it decreases the amount of oxyhaemoglobin produced.
Therefore, oxygen transport through blood is decreased.
What is the cause for nearly 90% of lung cancer?
due to smoking
What does tobacco smoke contain?
large number of cancer-causing substances/ (carcinogens)
What does tobacco smoke contain?
large number of cancer-causing substances/ (carcinogens)
With the long term exposure to cigarette smoke, explain the formation of a cancer
Long term exposure to such chemicals in cigarette smoke results in the proliferation of cells in the bronchial epithelium, forming a mass of abnormal cells.
How would a cancer spread among the body?
Does Passive or second hand smoking will also result in the mentioned ill effects of smoking?
Yes
