Assignment Code: BBCCT-115/TMA/2022

Course Code: BBCCT-115

Assignment Name: Human Physiology

Year: 2022

Verification Status: Verified by Professor

Maximum Marks:100

Note: Attempt all questions. The marks for each question are indicated against it.

PART- I Maximum marks: 50

Q1. (a) Define the following terms: (1x5=5)

(i) Human physiology

Ans) Human physiology is the science of how the human body functions in health and disease. A degree in human physiology provides excellent preparation for careers or graduate study in biomedical research and the health professions or related disciplines.

(ii) Extracellular fluid

Ans) In cell biology, extracellular fluid denotes all body fluid outside the cells of any multicellular organism. Total body water in healthy adults is about 60% of total body weight; women and the obese typically have a lower percentage than lean men.

(iii) Breathing

Ans) Breathing is the process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen.

(iv) Blood clotting

Ans) Coagulation, also known as blood clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in haemostasis, the cessation of blood loss from a damaged vessel, followed by repair.

(v) Cardiac output

Ans) Cardiac output, also known as heart output, denoted by the symbols Q, or {\dot Q}_{{c}}, is a term used in cardiac physiology that describes the volume of blood being pumped by both ventricles of the heart, per unit time.

(b) Explain what is homeostatic control system. (5)

Ans) The control system for regulation of homeostasis is an open system, which involves stimulus as input and response as output.

Control system or homeostasis regulation involves five basic components:

1. Any physical, chemical, or environmental variables or disruption that produces a divergence from the typical body's environment is referred to as a stimulus.

2. The signal is received by the receptor, which then sends it to the control centre. Consider neurons.

3. The control centre, also known as the coordination centre, receives and analyses information from the receptor. For any physiological activity, it establishes a normal reference point or setup point. Hypothalamus or brain, for example.

4. The control centre tells the effector how to react to the stimulus. Glands and muscles, for example.

5. The response is the body's response to the stimulus. It is a corrective action taken in response to the disturbance. It has the ability to either oppose or intensify the stimuli. Each physiological process has its own setup point or reference point. The control system is activated when there is a departure from the reference point. The control system is always feed-backed after optimising the physiological process to its reference point. The feed-back mechanism is the name for the control system. A feed-back system can be one of two types:

i) Negative feed-back mechanism

ii) Positive feed-back mechanism

Q2. Discuss various components of blood. (10)

Ans) The main components of blood are:

Red blood cells, white blood cells, and platelets are suspended in plasma, which is the liquid component of blood. It makes up more than half of the volume of blood and is largely made up of water with dissolved ions and proteins. Albumin is the most abundant protein in plasma. Albumin binds to and transports chemicals like hormones and certain medications, preventing fluid from leaking out of blood vessels and into tissues. Antibodies, which actively fight the body against viruses, bacteria, fungi, and cancer cells, and clotting factors, which control bleeding, are among the other proteins found in plasma.

Red blood cells account for approximately 40% of the amount of blood. Haemoglobin, a protein that gives blood its red colour and allows it to transport oxygen from the lungs to all body tissues, is found in red blood cells. Cells use oxygen to generate energy for the body, leaving carbon dioxide as a waste product. Carbon dioxide is carried away from the tissues and returned to the lungs by red blood cells. Blood delivers less oxygen when the number of red blood cells is too low, resulting in weariness and weakness.

White blood cells (also known as leukocytes) are smaller than red blood cells, with approximately one white blood cell for every 600 to 700 red blood cells. White blood cells are primarily important for protecting the body against infection.

Platelets: Platelets aid in the clotting process by clumping together at a bleeding site to create a plug that seals the blood vessel. At the same time, they release chemicals that aid in the formation of new clots. Bruising and irregular bleeding are more frequent when the quantity of platelets in the blood is too low (thrombocytopenia). When the amount of platelets in the blood is too high (thrombocythemia), blood might clot too much and block blood vessels, producing problems like a transient ischemic stroke. Platelets can absorb clotting proteins and, ironically, promote bleeding when the number of platelets is extremely high.

Q3. (a) Discuss internal structure of heart with the suitable diagram. (5)

Ans) The heart’s contraction cycle follows a dual pattern of circulation—the pulmonary (lungs)and systemic (body) circuits—because of the pairs of chambers that pump blood into the circulation. In order to develop a more precise understanding of cardiac function, it is first necessary to explore the internal anatomical structures in more detail.

The word septum is derived from the Latin for “something that encloses;” in this case, a septum (plural = septa) refers to a wall or partition that divides the heart into chambers.

Valves of the Heart: the septum between the atria and ventricles is known as the atrioventricular septum. It is marked by the presence of four openings that allow blood to move from the atria into the ventricles and from the ventricles into the pulmonary trunk and aorta.

Located in each of these openings between the atria and ventricles is a valve, a specialized structure that ensures one-way flow of blood. The valves between the atria and ventricles are known generically as  the tricuspid (right side)and the bicuspid (left side) valve. The valves at the openings that lead to the pulmonary trunk and aorta are known generically as the pulmonary and the aortic valve.

This anterior view of the heart shows the four chambers, the major vessels, and their early branches as well as the valves.

(b) Give a brief account on human respiratory system. (5)

Ans) The respiratory system is the network of organs and tissues that help you breathe. It includes your airways, lungs and blood vessels. The muscles that power your lungs are also part of the respiratory system. These parts work together to move oxygen throughout the body and clean out waste gases like carbon dioxide.

The respiratory system has many different parts that work together to help you breathe. Each group of parts has many separate components. Your airways deliver air to your lungs. Your airways are a complicated system that includes your:

1. Mouth and nose: Openings that pull air from outside your body into your respiratory system.

2. Sinuses: Hollow areas between the bones in your head that help regulate the temperature and humidity of the air you inhale.

3. Pharynx (throat): Tube that delivers air from your mouth and nose to the trachea (windpipe).

4. Trachea: Passage connecting your throat and lungs.

5. Bronchial tubes: Tubes at the bottom of your windpipe that connect into each lung.

6. Lungs: Two organs that remove oxygen from the air and pass it into your blood.

Q4. Differentiate between: (5+5=10)

(a) Glomerular filtration and tubular reabsorption

Ans) Glomerular filtration: Glomerular filtration is the first step of filtering blood and urine production. The dissolved ions in blood plasma pass across the wall of glomerular capillaries into the glomerular capsule and then into the renal tubule. The glomerular filtration takes place through a semipermeable filtration membrane of the glomerular capillaries into the capsular space of Bowman’s capsule. This liquid which is filtered from blood along with many different substances is known as ‘glomerular filtrate’. The high pressure is required for the effective filtration due to various filtration forces.

Tubular reabsorption: When filtered fluid move through the renal tubule and the collecting duct, tubule cells reabsorb about 99% of the filtered fluid (water and other solutes) which return to the blood stream through the peritubular capillaries and vasa recta. The term reabsorption means return of filtered substances to the bloodstream. Tubular reabsorption is the second step in urine formation. As the glomerular filtrate passes from Bowman’s capsule to PCT of renal tubule, certain useful substances including most of the water, electrolytes and organic nutrients such as glucose, amino acids, vitamins etc. are selectively reabsorbed from the filtrate back into the blood. There is a valid logic behind first filtering out large quantities of water and different substances into the glomerular filtrate, and then reabsorbing them back into the blood.

(b) Arteries and veins

Ans) The difference between Arteries and veins is as follows:

Q5. Write short notes on the following: (5+5=10)

(a) Hypoxia

Ans) Hypoxia is a state in which oxygen is not available in sufficient amounts at the tissue level to maintain adequate homeostasis; this can result from inadequate oxygen delivery to the tissues either due to low blood supply or low oxygen content in the blood (hypoxemia). Hypoxia can vary in intensity from mild to severe and can present in acute, chronic, or acute and chronic forms. The response to hypoxia is variable; while some tissues can tolerate some forms of hypoxia/ischemia for a longer duration, other tissues are severely damaged by low oxygen levels.

Some of the most common causes of hypoxemia include:

1. Heart conditions, including heart defects

2. Lung conditions such as asthma, emphysema, and bronchitis

3. Locations of high altitudes, where oxygen in the air is lower

4. Strong pain medications or other problems that slow breathing

5. Sleep apnoea (impaired breathing during sleep)

6. Inflammation or scarring of the lung tissue (as in pulmonary fibrosis)

(b) Glomerulonephritis

Ans) Glomerulonephritis is an inflammation of the kidney's small filters. The urine excretes the surplus fluid and trash that glomeruli remove from the bloodstream. Glomerulonephritis can strike quickly or develop over time. Glomerulonephritis can occur on its own or as part of a more serious condition like lupus or diabetes. Glomerulonephritis can cause kidney damage if the inflammation is severe or lasts for a long time. The glomerulus is the filtration unit of the kidney. There are thousands of glomeruli in each kidney. The glomeruli aid in the removal of toxic substances from the body. Glomerulonephritis can be brought on by issues with the immune system. The specific source of this illness is frequently unknown. Blood and protein are lost in the urine when the glomeruli are damaged. Kidney function can be lost in weeks or months if the illness progresses aggressively. Rapidly progressing glomerulonephritis is the medical term for this condition.

PART-II

Maximum marks: 50

Q6. What is digestion? Describe gastrointestinal tract with labelled diagram. (10)

Ans) Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream

The gastrointestinal tract is the digestive system's tract or conduit that runs from the mouth to the anus. In humans and other animals, the GI tract houses all of the digestive system's major organs, such as the oesophagus, stomach, and intestines. Food is consumed by the mouth, which is then digested to extract nutrients and absorb energy, with waste being ejected through the anus as faeces. The term "gastrointestinal" refers to the stomach and intestines as an adjective.

The oesophagus, stomach, and intestines make up the human gastrointestinal system, which is separated into upper and lower gastrointestinal tracts. The GI tract encompasses all structures between the mouth and the anus, forming a continuous tube that includes the stomach, small intestine, and large intestine, as well as the main organs of digestion. The gastrointestinal tract, as well as the digestive organs that support it, make up the entire human digestive system (the tongue, salivary glands, pancreas, liver and gallbladder). The tract can also be separated into three segments: foregut, midgut, and hindgut, based on their embryological origins. At autopsy, the entire human GI system is around nine metres (30 feet) long. The intestines, which are tubes of smooth muscle tissue, maintain a continuous muscle tone in a halfway-tense condition throughout the live organism, but can relax in areas to allow for local distention and peristalsis.

The gut microbiota, which contains about 4,000 different types of bacteria that play various functions in immunological health and metabolism, as well as many other microorganisms, is found in the gastrointestinal system. Hormones are released by cells in the GI tract to help regulate the digestive process. Gastrin, secretin, cholecystokinin, and ghrelin are digestive hormones that are mediated by either intracrine or autocrine pathways, showing that the cells that release these hormones have remained relatively unchanged throughout evolution.

Q7. Explain the structure and function of liver. (10)

Ans) Structure of Liver

1. The liver is reddish-brown in colour and has a rubbery feel, weighing between 3.17 and 3.66 pounds (lb) or 1.44 and 1.66 kilogrammes (kg). It is found above and to the left of the stomach, as well as beneath the lungs.

2. The only organ that is heavier and larger than the liver is the skin.

3. The liver has two lobes: a larger right lobe and a smaller left lobe. It is generally triangular in shape. The falciform ligament, a band of tissue that keeps the diaphragm anchored, separates the lobes.

4. Glisson's capsule is a fibrous tissue layer that surrounds the outside of the liver. The peritoneum, a membrane that forms the lining of the abdominal cavity, further protects this capsule.

5. This aids in the retention of the liver and protects it from physical harm.

Functions of Liver

1. Bile production: Bile aids in the digestion and absorption of fats, cholesterol, and certain vitamins in the small intestine. Bile salts, cholesterol, bilirubin, electrolytes, and water make up bile.

2. The iron liberated from haemoglobin is stored in the liver or bone marrow and used to create the next generation of blood cells.

3. Vitamin K is required for the production of certain coagulants, which aid in the clotting of blood. Bile is produced in the liver and is necessary for vitamin K absorption. Clotting factors cannot be created if the liver does not produce enough bile.

4. Bile is a digestive enzyme that breaks down fats and makes them easier to digest.

5. Carbohydrates are stored in the liver, where they are broken down into glucose and released into the bloodstream to keep blood glucose levels normal. They are stored as glycogen and released when an energy burst is required.

6. Vitamin and mineral storage: Vitamins A, D, E, K, and B12 are all stored in the liver. It stores a substantial amount of these vitamins. The liver stores iron from haemoglobin in the form of ferritin, which is ready to be used in the production of new red blood cells. Copper is stored and released by the liver.

7. Aids in the digestion of proteins

8. The blood is filtered.

9. The liver is a component of the mononuclear phagocyte system, which plays an important role in immunity. It has a large amount of Kupffer cells, which play an important role in immunological function. Any disease-causing substances that enter the liver through the gut are destroyed by these cells.

10. Albumin production: Albumin transfers fatty acids and steroid hormones to assist maintain proper pressure and prevent blood vessel leakage.

11. Synthesis of angiotensinogen: When the kidneys produce an enzyme called renin, this hormone raises blood pressure by constricting blood vessels.

Q8. Differentiate between: (5+5=10)

(a) Smooth muscles and skeletal muscle cells

Ans) The differences between smooth muscles and skeletal muscle cells are:

(b) Spermatogenesis and Oogenesis

Ans) The differences between smooth muscles and skeletal muscle cells are:

Q9. (a) Explain the structure and function of bone. (5)

Ans) The structure of bone is as follows:

Compact bone is made up of tightly packed osteons, also known as haversian systems. The osteon is made up of concentric rings (lamellae) of matrix that surround a central canal termed the osteonic (haversian) canal. The bone cells (osteocytes) are found in spaces called lacunae between the matrix rings.

The function of bone is as follows:

1. Supporting and assisting your movement. Your bones literally support your body and prevent it from collapsing. Your bones play a role in your posture.

2. Keeping your interior organs safe. Your bones protect your organs against injuries such as strong hits, punctures, and other types of trauma.

3. Your blood cells are being made. Platelets, red blood cells, and white blood cells are all made by different types of bones. These cells are created within your bones. Platelets aid in the clotting of blood, red blood cells provide oxygen to your organs, and white blood cells combat infection.

4. Fat storage and release When your body requires energy, certain types of bones store fat and then release it.

5. Mineral storage and release When the amounts of certain minerals in your blood are too high, your bones can store them. When your body need minerals, your bones will release them. Calcium, phosphorus, and vitamin D are examples of these minerals.

(b) Explain neuron with schematic diagram. (5)

Ans) A neuron is a specialized cell, primarily involved in transmitting information through electrical and chemical signals. They are found in the brain, spinal cord and the peripheral nerves. A neuron is also known as the nerve cell.

The structure of a neuron varies with their shape and size and it mainly depends upon their functions and their location. Neurons are the structural and functional units of the nervous system. A group of neurons forms a nerve. Neurons are the structural and functional units of the nervous system.

In humans, there are two types of neurons:

1. Sensory Neurons

2. Motor Neurons

The neuron is a specialized and individual cell, which is also known as the nerve cell.  A group of neurons forms a nerve.

Q10. Write short notes on the following: (5+5=10)

(a) Neurotransmitters

Ans) Neurotransmitters are often referred to as the body’s chemical messengers. They are the molecules used by the nervous system to transmit messages between neurons, or from neurons to muscles. Communication between two neurons happens in the synaptic cleft (the small gap between the synapses of neurons). Here, electrical signals that have travelled along the axon are briefly converted into chemical ones through the release of neurotransmitters, causing a specific response in the receiving neuron. A neurotransmitter influences a neuron in one of three ways: excitatory, inhibitory or modulatory. An excitatory transmitter promotes the generation of an electrical signal called an action potential in the receiving neuron, while an inhibitory transmitter prevents it. Whether a neurotransmitter is excitatory or inhibitory depends on the receptor it binds to.

(b) Role of brain in learning and memory

Ans) The brain is the organ that is responsible for what we call the mind. It is the basis for thinking, feeling, wanting, perceiving, learning and memory, curiosity, and behavior. Memory is a fundamental mental process, and without memory we are capable of nothing but simple reflexes and stereotyped behaviours. Thus, learning and memory is one of the most intensively studied subjects in the field of neuroscience. There are different kinds of memory. Some memories, such as those concerning events and facts, are available to our consciousness; this type of memory is called “declarative memory.” However, another type of memory, called “procedural memory,” is not available to consciousness. This is the memory that is needed, for example, to use a previously learned skill. We can improve our skills through practice. With training, the ability to play tennis, for example, will improve. Declarative memory and procedural memory are independent.