Transport in humans Flashcards
What do unicellular organisms rely on for movement of substances in and out of the cell?
Diffusion
Unicellular organisms are small enough that diffusion distances are short, allowing for quick substance movement.
Why can’t multicellular organisms rely solely on diffusion?
Distances are too big, risking cell death before materials can diffuse in and out
Multicellular organisms require transport systems to efficiently move substances.
What type of circulatory system do humans have?
Double circulatory system
In a double circulatory system, blood passes through the heart twice in a full cycle.
What is the flow of oxygenated blood in the human heart?
From the lungs to the left atrium, then to the left ventricle and out through the aorta
Oxygenated blood is delivered to the body from the left side of the heart.
What is the flow of deoxygenated blood in the human heart?
From the body to the right atrium, then to the right ventricle and out through the pulmonary artery
Deoxygenated blood returns from the body to the right side of the heart for reoxygenation.
What happens to blood when it enters the atria?
The walls of the atria contract, increasing pressure and forcing blood through the valves into the ventricles
This process initiates the cycle of blood flow through the heart.
What occurs when the ventricles are full?
They contract, increasing the pressure of the blood in the ventricles
This contraction is crucial for ejecting blood into the aorta and pulmonary artery.
What closes the valves after the ventricles empty?
Higher pressure in the aorta and pulmonary artery
This pressure prevents backflow of blood into the ventricles.
Fill in the blank: The blood enters the _______ before being pumped into the ventricles.
atria
Atria are the upper chambers of the heart that receive blood.
True or False: The cycle of blood flow through the heart is continuous.
True
The heart continuously pumps blood in a cycle to maintain circulation.
What does the right atrium receive?
Deoxygenated blood from the vena cava
The vena cava is a large vein that carries deoxygenated blood to the heart.
Where does blood go after the right ventricle?
To the lungs through the pulmonary artery
The pulmonary artery is responsible for carrying deoxygenated blood from the heart to the lungs for oxygenation.
What type of blood does the left atrium receive?
Oxygenated blood from the lungs via the pulmonary vein
The pulmonary vein is the vessel that carries oxygenated blood back to the heart.
What happens to oxygenated blood in the left ventricle?
It gets pumped to the rest of the body through the aorta
The aorta is the largest artery in the body, distributing oxygenated blood to all parts.
What is the function of the heart valves?
Prevent the back flow of blood
Valves ensure unidirectional blood flow through the heart chambers.
Why is the muscle thicker on the left side of the heart?
It needs to pump blood around the whole body
The left side of the heart works harder than the right side due to the higher pressure required to circulate blood throughout the body.
What is the function of bicuspid and tricuspid valves?
Prevent back flow of blood from ventricles to aorta when relaxed
Bicuspid (mitral) valve is on the left side, and tricuspid valve is on the right side of the heart.
What do semi-lunar valves prevent?
Back flow of blood into the ventricles when relaxed
Semi-lunar valves are located at the exit of the ventricles leading to the aorta and pulmonary artery.
What is the primary function of arteries?
Carry blood away from the heart
Arteries are responsible for transporting oxygenated blood (except for the pulmonary arteries) to various body tissues.
Describe the structure of arteries.
Thick walls of muscle and elastic fibres, narrow lumen
These adaptations help arteries withstand and maintain high blood pressure.
What is the primary function of veins?
Carry blood towards the heart
Veins generally carry deoxygenated blood (except for the pulmonary veins).
How do the walls of veins compare to arteries?
Veins have thinner walls and wider lumen
This structure accommodates lower blood pressure in veins.
What assists blood flow in veins back to the heart?
Gravity or contracting skeletal muscles
Skeletal muscle contractions help propel blood through the veins, especially in the limbs.
What is the function of valves in the circulatory system?
Prevent blood flow in the wrong direction
What happens to blood after a contraction in the veins?
It gets pushed through the next valve
What are capillaries primarily responsible for?
Exchange of materials
Describe the walls of capillaries.
Thin, permeable, only one cell thick
What substances can diffuse through capillary walls?
Oxygen, carbon dioxide, other products, waste products
What is the blood pressure and flow rate like in capillaries?
Low blood pressure and slow flow rate
What are the main components of blood?
Platelets, plasma, red blood cells, white blood cells (phagocytes, lymphocytes)
What is plasma?
The liquid part of the blood, mainly water with dissolved minerals
What does plasma transport?
Carbon dioxide, glucose, urea, hormones, amino acids, antibodies, heat energy
What is the role of the pulmonary artery?
Carries deoxygenated blood from the heart to the lungs
What is the function of the vena cava?
Returns deoxygenated blood to the heart
What is the function of the pulmonary vein?
Carries oxygenated blood from the lungs to the heart
What does the aorta do?
Distributes oxygenated blood from the heart to the body
What is the hepatic portal vein’s function?
Transports blood from the gut to the liver
What is the role of the renal artery?
Supplies blood to the kidneys
What does the renal vein do?
Carries filtered blood away from the kidneys
List the major components of the circulatory system.
- Heart
- Blood vessels
- Blood
True or False: Capillaries have thick walls to withstand high pressure.
False
What is the primary function of red blood cells?
Red blood cells carry oxygen and are adapted to be more efficient at transporting oxygen.
Red blood cells have specialized structures that enhance their oxygen-carrying capabilities.
What shape do red blood cells have and why is it beneficial?
Biconcave disk shape increases the surface area for oxygen diffusion.
This shape allows for a greater rate of oxygen exchange between the cell and its environment.
Why do red blood cells lack a nucleus?
They have no nucleus so they can carry more oxygen.
The absence of a nucleus allows for more space to store hemoglobin.
What is the role of hemoglobin in red blood cells?
Hemoglobin binds with oxygen to transport it.
The reaction is represented as Hemoglobin + Oxygen → oxyhemoglobin.
Where are red blood cells made?
Made in bone marrow.
Bone marrow is the primary site of red blood cell production in the body.
What is a key characteristic of white blood cells?
They contain a nucleus.
This distinguishes them from red blood cells and is important for their function.
What are the two main types of white blood cells?
Phagocytes and lymphocytes.
Each type has distinct roles in the immune response.
What is the function of phagocytes?
Engulf and digest pathogens through phagocytosis.
Phagocytes play a crucial role in the body’s defense against infections.
Describe the process of phagocytosis.
- White blood cell encounters a pathogen.
- Binds to the membrane.
- Membrane surrounds the bacterium, engulfing it.
- Vesicle containing the pathogen separates and moves to cytoplasm.
- Lysosomes release digestive chemicals into the vesicle.
- Pathogen is killed and digested.
- Waste is released.
This process is essential for clearing infections.
What do lymphocytes produce?
Antibodies and antitoxins.
Antibodies bind to specific antigens on pathogens, while antitoxins neutralize toxins from pathogens.
True or False: Lymphocytes can only produce antibodies.
False.
Lymphocytes produce both antibodies and antitoxins.
What are the different ways in which antibodies work?
Label cells for phagocytosis.
Cause the cells to burst.
Clump cells together so they are more easily engulfed by a phagocyte.
Destroy toxins produced by pathogens.
What are memory cells?
Some white blood cells that become memory cells after infection or vaccination
Memory cells produce antibodies sooner, quicker, and in greater quantities during secondary immune responses.
What is the secondary immune response?
The response generated by memory cells producing antibodies more effectively during subsequent infections
This response is quicker and occurs after initial exposure to an antigen.
How does vaccination work?
The body is given antigens of an infection through a weakened pathogen, dead pathogen, or just the antigens
This leads to the production of antibodies and the creation of memory cells.
What are platelets responsible for?
Clotting, helping to stop blood loss and prevent the entry of pathogens
Platelets convert soluble fibrinogen into insoluble fibrin to form a mesh at the wound.
What do platelets convert soluble fibrinogen into?
Insulin fibrin
This conversion is essential for forming a mesh that leads to a scab or clot.
Define pathogens.
Organisms that can cause disease
Pathogens include fungi, bacteria, protoctists, and viruses.
Are viruses considered living organisms?
No
Viruses are parasitic and can only reproduce inside living or host cells.
What is the structure of a virus?
A protein coat and unbound loose genetic material (either DNA or RNA)
Viruses lack cellular structure.
Give an example of a virus and what disease it causes.
Influenza, which causes flu
Other examples include HIV (causes AIDS) and Tobacco Mosaic Virus (infects plant cells).
Fill in the blank: Pathogens may be ______, bacteria, protoctists, or viruses.
fungi
What role do memory cells play in the immune system?
They produce antibodies to combat further infections more effectively - producing antibodies sooner, quicker and in greater quantities.
This enhances the body’s ability to respond to pathogens it has encountered before.
What are protoctists?
Microscopic single celled organisms.
Some protoctists like Amoeba resemble animal cells, while others like Chlorella have chloroplasts and are more plant-like.
What is a pathogenic example of a protoctist?
Plasmodium, responsible for causing malaria.
Plasmodium is a genus of protoctists that infects humans and is transmitted by mosquitoes.
What happens to heart rate during exercise?
Heart rate increases.
This occurs because muscles need more energy, leading to increased respiration and a higher demand for oxygen and glucose.
What are the main factors increasing the risk of coronary heart disease?
• Smoking
• High saturated fats/cholesterol diet
• Lack of exercise
• Stress
• High BMI
• High blood pressure
• Heredity
Each of these factors contributes to the damage of coronary arteries and increases the risk of heart disease.
How does smoking contribute to coronary heart disease?
It damages the lining of arteries and increases heart strain.
Carbon monoxide from smoking binds to hemoglobin, reducing oxygen transport and increasing heart strain.
What role does exercise play in reducing the risk of coronary heart disease?
It improves blood movement and strengthens the heart.
Regular exercise can prevent the formation of atheromas, which are fatty deposits in arteries.
Fill in the blank: Coronary heart disease occurs when there is a fatty deposit in the artery which _______.
blocks it.
A blood clot can also block the artery, leading to a heart attack.
What is the relationship between cholesterol and coronary heart disease?
Cholesterol can build up on artery walls and block them.
This buildup can lead to atherosclerosis, increasing the risk of heart attacks.
True or False: A high BMI is a risk factor for coronary heart disease.
True.
Being overweight increases the likelihood of developing coronary heart disease due to various metabolic changes.
What is one method to treat coronary heart disease?
Using a piece of vein to stretch around the blockage in the artery or placing a stent in the artery
What can cause a heart attack?
Reduced circulation in the coronary arteries
What happens when there is no oxygen and glucose delivered to the heart muscles?
No aerobic respiration occurs
What is the consequence of no aerobic respiration in heart muscles?
No energy is released for muscle contractions
What type of respiration occurs when oxygen is not available?
Anaerobic respiration
What does anaerobic respiration in muscle cells produce?
Lactic acid
What is the effect of lactic acid on muscle cells?
It denatures the enzymes in the muscle cells, causing them to die
How does a heart attack affect circulation to the rest of the body?
Circulation is reduced as the heart cannot contract and pump blood efficiently
What is released when an organism is threatened?
Adrenaline
What effect does adrenaline have on the heart?
Causes the heart to contract more frequently and with more force
What happens to heart rate when adrenaline is released?
Heart rate increases
What does increased heart rate and contraction achieve?
Increases the oxygen supply to the muscles
Fill in the blank: When an organism is threatened, _______ is released to prepare the body for action.
adrenaline
