Exam Revision using learning objectives

Question 1

Define atomic number

Answer 1

It tells you how many protons are in the nucleus of an atom.

Question 2

Define atomic weight

Answer 2

It takes into account the mass of protons, neutrons, and electrons within an atom.

Question 3

Define molecular weight

Answer 3

Molecular weight, also known as molar mass, is the sum of the atomic weights of all the atoms in a molecule. It is calculated by adding up the atomic weights of each individual atom in the molecule.

Question 4

Define ion

Answer 4

An ion is an atom or molecule that has gained or lost electrons, resulting in a net electric charge.
Cation is a positive charge
Anion is a negative charge

Question 5

Define electrolyte

Answer 5

It is an ionic compund

Question 6

Define pH

Answer 6

pH is a measure of the acidity or alkalinity of a solution. It quantifies the concentration of hydrogen ions (H+) in a solution. The pH scale ranges from 0 to 14, where a pH of 7 is considered neutral. A pH value below 7 indicates acidity, with lower values indicating stronger acidity. Conversely, a pH above 7 indicates alkalinity or basicity, with higher values indicating stronger alkalinity.

Question 7

Define acid

Answer 7

Low pH

Question 8

Define alkali

Answer 8

High pH

Question 9

Describe the structure of an atom

Answer 9

A nucleus that contains protons and neutrons, with electrons surrounding the outside

Question 10

Understand the difference between ionic and covalent bonds

Answer 10

Iconic bons are when electons are given away, covalent bonds are when electrons are shared.

Question 11

Outline the concept of molar concentration

Answer 11

It is the measure of the amount solute in a solvent

Question 12

Explain the importance of buffers in regulation of pH of body fluids and tissues

Answer 12

Buffers are essential in regulating the pH of body fluids and tissues. They help maintain the optimal pH range required for enzymatic activity, protein structure, oxygen transport, acid-base balance, and proper nerve and muscle function. By resisting changes in pH, buffers contribute to overall physiological stability and ensure the proper functioning of various cellular processes.

Question 13

Describe in simple terms the chemical nature of sugars

Answer 13

Sugars are simple carbohydrates that serve as a source of energy for the body. They are made up of carbon, hydrogen, and oxygen atoms arranged in a specific structure. Sugars can be either monosaccharides (single sugar units) like glucose or fructose, or they can be disaccharides (two sugar units linked together) like sucrose or lactose.

Question 14

Describe in simple terms the chemical nature of proteins

Answer 14

Proteins are complex molecules made up of chains of amino acids. Amino acids are small compounds that contain carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur atoms. The sequence and arrangement of amino acids determine the shape and function of a protein. Proteins have diverse roles in the body, including providing structure to cells and tissues, facilitating chemical reactions as enzymes, and serving as transporters and messengers.

Question 15

Describe in simple terms the chemical nature of lipids

Answer 15

Lipids are a group of molecules that include fats, oils, and waxes. They are composed of carbon, hydrogen, and oxygen atoms, with some types of lipids also containing phosphorus and nitrogen. Lipids are hydrophobic, meaning they do not dissolve in water. They serve as an energy storage form, provide insulation and protection for organs, and are important components of cell membranes.

Question 16

Describe in simple terms the chemical nature of nucleotides

Answer 16

Nucleotides are the building blocks of nucleic acids, such as DNA and RNA. They consist of three main components: a sugar molecule (ribose or deoxyribose), a phosphate group, and a nitrogenous base (adenine, cytosine, guanine, thymine, or uracil). Nucleotides are involved in genetic information storage and transfer, as well as energy transfer in cells (e.g., ATP - adenosine triphosphate).

Question 17

Describe in simple terms the chemical nature of enzymes

Answer 17

Enzymes are specialized proteins that act as catalysts in biological reactions. They speed up chemical reactions in the body by lowering the energy required for the reaction to occur. Enzymes are highly specific, meaning each enzyme catalyzes a particular reaction or group of reactions. They enable essential processes in the body, such as digestion, metabolism, and DNA replication, by facilitating chemical transformations without being consumed in the process.

Question 18

List the important roles that sugars play in the human body

Answer 18

Energy source: Sugars, such as glucose, provide the primary fuel for cellular energy production through processes like glycolysis and cellular respiration.
Cell signaling: Some sugars act as signaling molecules that help regulate various physiological processes in the body.
Structural support: Sugars contribute to the structure of certain molecules like glycoproteins and glycolipids, which are important for cell recognition and communication.

Question 19

List the important roles that proteins play in the human body

Answer 19

Enzymes: Proteins function as enzymes, catalyzing chemical reactions in the body and facilitating various biochemical processes.
Structural support: Proteins provide structural support to cells and tissues, maintaining their integrity and shape.
Transport and storage: Proteins serve as carriers and transport molecules for various substances, such as oxygen (hemoglobin) and lipids (lipoproteins). They also store essential molecules like iron (ferritin).
Immune system function: Antibodies, a type of protein, help defend the body against pathogens by recognizing and neutralizing foreign substances.
Hormones and signaling: Certain proteins, such as insulin, act as hormones or signaling molecules, regulating physiological processes like metabolism and growth.

Question 20

List the important roles that lipids play in the human body

Answer 20

Energy storage: Lipids, in the form of triglycerides, store energy in adipose tissue and provide a concentrated source of energy.
Insulation and protection: Lipids, particularly adipose tissue, act as insulation and cushioning, protecting organs and providing thermal insulation.
Component of cell membranes: Lipids, especially phospholipids, are vital components of cell membranes, maintaining their structure and regulating cellular processes.
Hormone production: Certain lipids, such as cholesterol, are involved in the synthesis of hormones like estrogen and testosterone.

Question 21

List the important roles that nucleotides play in the human body

Answer 21

Genetic information: Nucleotides are the building blocks of DNA and RNA, carrying and transmitting genetic information.
Energy currency: Nucleotides like ATP (adenosine triphosphate) store and transfer energy within cells, fueling various metabolic processes.
Coenzymes: Nucleotides function as coenzymes, assisting enzymes in carrying out biochemical reactions in the body.

Question 22

List the important roles that enzymes play in the human body

Answer 22

Catalysis: Enzymes accelerate chemical reactions by lowering the activation energy required for the reaction to occur, allowing essential processes to happen at a faster rate.
Metabolism regulation: Enzymes play a crucial role in metabolic pathways, facilitating the breakdown of nutrients and the synthesis of essential molecules.
Digestion: Digestive enzymes help break down food into smaller molecules that can be absorbed and utilized by the body.
DNA replication and repair: Enzymes are involved in DNA replication, ensuring accurate transmission of genetic information, as well as in DNA repair processes.

Question 23

Compare and contrast the processes of osmosis and diffusion

Answer 23

Osmosis and diffusion are both passive transport processes that occur down a concentration gradient. Diffusion is the movement of any type of particle from high to low concentration, while osmosis specifically involves the movement of water molecules across a semipermeable membrane in response to solute concentration differences.

Question 24

Describe the structure of the plasma membrane

Answer 24

The plasma membrane’s structure provides a dynamic and flexible barrier that protects the internal environment of the cell while allowing necessary interactions and exchanges with the external environment.

Question 25

Outline the life cycle of a cell

Answer 25

Interphase:
a. G1 phase (Gap 1): The cell grows, carries out its normal functions, and prepares for DNA replication.
b. S phase (Synthesis): DNA replication occurs, resulting in the duplication of the cell’s genetic material.
c. G2 phase (Gap 2): The cell continues to grow and prepares for cell division.

Mitosis (M phase):
a. Prophase: Chromosomes condense, the nuclear membrane disintegrates, and the spindle apparatus forms.
b. Metaphase: Chromosomes align at the center of the cell along the metaphase plate.
c. Anaphase: Sister chromatids separate and move towards opposite poles of the cell, pulled by the spindle fibers.
d. Telophase: Chromosomes reach the poles, the nuclear membrane reforms around each set of chromosomes, and the spindle apparatus disintegrates.
e. Cytokinesis: The cytoplasm divides, forming two daughter cells. In animal cells, a cleavage furrow forms, while in plant cells, a cell plate develops.

Question 26

Define differentiation

Answer 26

Differentiation is the process in which cells change from being unspecialized to having specific structures and functions. It allows cells to become specialized and perform specific tasks in the body. This process happens through a series of changes in gene expression and protein production. Differentiation is important for the development of organisms and for repairing and maintaining tissues. It occurs by following signals and cues that determine the cell’s fate and function. Overall, differentiation helps create different cell types with unique roles in the body.

Question 27

Define the term stem cell

Answer 27

Stem cells are special cells that have the ability to develop into different types of cells in the body. They are like “blank slates” that can become various cell types, such as muscle cells, nerve cells, or blood cells. Stem cells are important because they have the potential to repair damaged tissues and organs. They can divide and make copies of themselves, as well as differentiate into specialized cells to replace or replenish damaged cells in the body.

Question 28

Define the process of mitosis

Answer 28

This process ensures that each daughter cell receives a complete set of chromosomes and that the genetic information is accurately passed on. Mitosis is crucial for growth, repair, and the production of new cells in the body.

1. Prophase: The chromosomes condense and become visible. The nuclear membrane starts to break down, and the spindle apparatus forms.
2. Metaphase: The chromosomes line up in the middle of the cell, forming a single line called the metaphase plate.
3. Anaphase: The sister chromatids separate and move towards opposite ends of the cell. They are pulled by the spindle fibers.
4. Telophase: The chromosomes reach the opposite poles of the cell. The nuclear membrane reforms around each set of chromosomes, and the spindle apparatus disintegrates.
5. Cytokinesis: The cytoplasm divides, forming two separate daughter cells. In animal cells, a cleavage furrow forms and pinches the cell in two. In plant cells, a cell plate forms to separate the cytoplasm.

Question 29

What is active transport?

Answer 29

Active transport allows cells to move substances against their concentration gradient, enabling them to regulate internal environments, transport essential nutrients, and maintain proper cellular functioning.

Question 30

What is passive transport?

Answer 30

passive transport is the spontaneous movement of molecules or ions across the cell membrane without the need for energy input. It occurs through diffusion or facilitated diffusion, ensuring the necessary exchange of substances for the cell’s functioning.

Question 31

What is bulk transport?

Answer 31

Bulk transport is the process by which large substances or a large amount of substances are transported into or out of the cell. It involves endocytosis to bring materials into the cell and exocytosis to release materials outside the cell. These processes play crucial roles in cellular functioning and maintaining the overall balance of the cell’s internal and external environments.
There are two main types of bulk transport:

Endocytosis: This process brings substances into the cell. The cell membrane surrounds the materials, forming a vesicle, and then pinches off to bring the vesicle inside the cell. Endocytosis is used to capture external molecules, particles, or even entire cells, and can be further divided into different types such as phagocytosis (engulfing solid particles) and pinocytosis (taking in fluid and dissolved substances).

Exocytosis: This process releases substances from the cell. It involves the fusion of membrane-bound vesicles containing the materials with the cell membrane, allowing the contents to be expelled outside the cell. Exocytosis is used to export molecules, waste products, or cell secretions.

Question 32

Simplify the structure and functions of epithelial tissue

Answer 32

Structure:
Epithelial tissue consists of tightly packed cells that form a continuous layer. The cells are closely connected to each other with minimal space between them. They are arranged in a sheet-like structure, with a free surface facing the outside or a body cavity, and a basal surface attached to a basement membrane.

Epithelial tissue plays a crucial role in protecting, absorbing, secreting, and sensing in the body. Its structure and functions are tailored to the specific needs of different organs and tissues, contributing to the overall functioning and well-being of the body.

Question 33

Outline the structure and function of epithelial membranes

Answer 33

Epithelial membranes are specialized structures that serve to protect, lubricate, absorb, secrete, and provide sensory information in the body. They play a crucial role in maintaining homeostasis and supporting the proper functioning of various organs and systems.

Mucous Membranes:
Structure: Mucous membranes line the cavities and surfaces that are open to the external environment, such as the respiratory, digestive, urinary, and reproductive tracts. They consist of a layer of epithelial cells supported by a layer of connective tissue called the lamina propria.
Function: Mucous membranes produce mucus, a sticky fluid that helps lubricate and protect the underlying tissues. They also play a role in absorption and secretion. For example, the mucous membranes in the respiratory tract help trap and expel foreign particles, while those in the digestive tract aid in nutrient absorption.

Serous Membranes:
Structure: Serous membranes line the internal cavities of the body, such as the pleural, pericardial, and peritoneal cavities. They consist of two layers: an inner layer of simple squamous epithelium called the visceral layer, which covers the organs, and an outer layer called the parietal layer, which lines the body wall. The two layers are separated by a thin fluid-filled space called the serous cavity.
Function: Serous membranes secrete a fluid called serous fluid, which acts as a lubricant, reducing friction between the organs and the body wall during movements. This allows the organs to slide smoothly against each other. Serous membranes also provide protection to the underlying organs.

Cutaneous Membrane (Skin):
Structure: The cutaneous membrane, commonly known as the skin, is the largest organ of the body. It consists of an outer layer of stratified squamous epithelium called the epidermis and an underlying layer of connective tissue called the dermis.
Function: The skin acts as a protective barrier against physical injury, UV radiation, pathogens, and dehydration. It helps regulate body temperature, provides sensory information, and plays a role in vitamin D synthesis. The skin also contains various accessory structures, such as hair, nails, and sweat glands.

Question 34

Simplify the structure and functions of connective tissue

Answer 34

Structure:
Connective tissue is composed of cells and an extracellular matrix. The cells in connective tissue include fibroblasts, adipocytes (fat cells), macrophages, and immune cells. The extracellular matrix consists of fibers (collagen, elastic fibers) and ground substance (gel-like substance) secreted by the cells.

Connective tissue has diverse functions in the body, including providing support, protection, transportation, energy storage, and participating in the immune response. It is a crucial component of the body’s structural integrity and overall functioning.

Question 35

Describe the structure and functions of muscle tissue

Answer 35

Structure:
Muscle tissue is classified into three main types: skeletal muscle, cardiac muscle, and smooth muscle.

Muscle tissue is composed of specialized cells called muscle fibers and is responsible for generating force, producing movement, and maintaining body posture. It plays a vital role in voluntary and involuntary movements, ranging from gross motor actions to intricate cellular functions, ensuring proper functioning and coordination of the body’s systems.

Question 36

Relate defects in cell division and differentiation to formation of cancer cells

Answer 36

Defects in cell division and differentiation can lead to the formation of cancer cells. When cells divide incorrectly, it can cause genetic mutations and instability. These mutations can disrupt the normal control of cell growth and division. Similarly, problems in cell differentiation can result in cells losing their specialized functions and becoming less mature. These changes contribute to uncontrolled cell growth and the development of cancer.

Question 37

Physical characteristics and functions of blood

Answer 37

• Blood is a red, fluid connective tissue.
• It has a pH of around 7.4 and a slightly higher viscosity than water.
• Blood constitutes about 7% to 8% of total body weight.

Question 38

Functions of major components of plasma

Answer 38

• Water in plasma helps maintain blood volume and regulates body temperature.
• Proteins in plasma, such as albumin, globulins, and fibrinogen, contribute to osmotic balance, transport of substances, and blood clotting.
• Electrolytes in plasma help maintain fluid balance and pH.
• Nutrients, hormones, and waste products are transported in plasma.

Question 39

What is Haematopoiesis

Answer 39

• Haematopoiesis is the process of blood cell formation.
• It occurs in the bone marrow, specifically in the spongy bone tissue.
• Stem cells differentiate into various blood cell types, including erythrocytes, leukocytes, and platelets.

Question 40

What is the Life cycle of erythrocytes

Answer 40

• Erythrocytes, or red blood cells, are formed in the bone marrow through haematopoiesis.
• They circulate in the bloodstream for about 120 days.
• Old or damaged erythrocytes are removed by the spleen and liver, and their components are recycled.

Question 41

Describe erythropoiesis and factors that influence it

Answer 41

• Erythropoiesis is the process of erythrocyte production.
• It is regulated by the hormone erythropoietin, which is secreted by the kidneys in response to low oxygen levels.
• Factors that influence erythropoiesis include iron availability, adequate nutrients (such as vitamin B12 and folic acid), and appropriate hormonal regulation.

Question 42

Roles of erythrocytes, leukocytes, and platelets

Answer 42

• Erythrocytes transport oxygen to body tissues and remove carbon dioxide.
• Leukocytes, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils, are involved in the immune response and defense against pathogens.
• Platelets aid in blood clotting and the formation of blood clots to prevent excessive bleeding.

Question 43

Stages of haemostasis and their purpose

Answer 43

• The stages of haemostasis are vascular spasm, platelet plug formation, and blood clotting (coagulation).
• Vascular spasm constricts blood vessels to reduce blood flow.
• Platelet plug formation involves platelets adhering to damaged blood vessel walls and forming a plug to stop bleeding.
• Coagulation involves a cascade of reactions that lead to the formation of a fibrin clot to reinforce the platelet plug and seal the wound.

Question 44

Basic blood tests and their clinical relevance

Answer 44

Basic blood tests, such as complete blood count (CBC), measure various components of blood, including red blood cells, white blood cells, and platelets.

They provide information about overall health, identify infections, evaluate oxygen-carrying capacity, assess clotting ability, and detect abnormalities such as anaemia or infection.

Question 45

Features of dyscrasias

Answer 45

Dyscrasias refer to abnormalities or disorders of the blood.

Examples include anaemia (low red blood cell count), leukocytosis (high white blood cell count), and thrombocytopenia (low platelet count).

Dyscrasias can have various causes, such as nutritional deficiencies, genetic disorders, autoimmune conditions, or underlying diseases.

Question 46

Name and outline the functions of the major tissue types

Answer 46

1. Epithelial tissue:
   Functions: Protection, absorption, secretion, and sensation. It covers body surfaces, lines cavities, and forms glands.
2. Connective tissue:
   Functions: Support, protection, insulation, and transportation. It connects and supports other tissues and organs.
3. Muscle tissue:
   Functions: Movement and generating force. It contracts to produce voluntary and involuntary movements.
4. Nervous tissue:
   Functions: Communication and coordination. It conducts electrical impulses and controls body functions.

Question 47

How each major tissue type is adapted to perform its functions

Answer 47

Epithelial tissue has tightly packed cells with specialized structures like microvilli and cilia for absorption and secretion.

Connective tissue has cells dispersed within an extracellular matrix that provides strength and flexibility.

Muscle tissue has contractile proteins that enable it to generate force and create movement.

Nervous tissue has specialized cells called neurons that transmit electrical signals for communication.

Question 48

Functions of the skin and its relation to structure

Answer 48

Functions: Protection against pathogens, UV radiation, and physical injury; regulation of body temperature; sensation; and vitamin D synthesis.

Structure: The skin has an outermost layer called the epidermis, which is composed of multiple layers of epithelial cells. The dermis lies beneath, providing strength and elasticity. Specialized structures like hair follicles, sweat glands, and sensory receptors are present within the skin.

Question 49

Risks associated with skin damage due to trauma or burns

Answer 49

Risk of infection: Damaged skin can provide an entry point for bacteria and other pathogens.

Dehydration: Loss of intact skin can result in fluid loss and potential complications.
Impaired thermoregulation: Damage to the skin can disrupt the body’s ability to regulate temperature.

Scarring and tissue damage: Severe trauma or burns can lead to scarring and long-term functional impairments.

Question 50

Role of bones, muscles, ligaments, and tendons

Answer 50

Bones provide support, protect organs, and allow movement through their rigid structure.
Muscles contract and generate force, enabling movement and maintaining posture.

Ligaments connect bones to other bones, providing stability and limiting excessive movement.

Tendons connect muscles to bones, allowing transmission of muscle forces to produce movement.

Question 51

Characteristics of bone, muscle, ligaments, and tendons that make them suited to their roles

Answer 51

Bones have a hard, mineralized matrix that provides strength and support.

Muscles contain contractile proteins that enable them to generate force and contract.

Ligaments are composed of dense connective tissue, providing strength and stability to joints.

Tendons have high tensile strength and are capable of withstanding the forces exerted by muscles.

Question 52

When tissues are damaged and the steps of the healing process

Answer 52

Tissues initiate an inflammatory response to remove damaged cells and debris.

New blood vessels form in the area to deliver oxygen, nutrients, and immune cells.

Cells called fibroblasts produce new collagen fibers, rebuilding the tissue.

Tissue remodeling and maturation occur, where the new tissue gains strength and functionality.

Question 53

Benefits of pain and inflammation

Answer 53

Pain acts as a protective mechanism, alerting the body to potential injury and preventing further damage.

Inflammation helps initiate the healing process by bringing immune cells and nutrients to the damaged area, fighting infection, and promoting tissue repair.

Question 54

Major types of joints

Answer 54

Fibrous joints: Connected by fibrous connective tissue and allow minimal to no movement.

Cartilaginous joints: Joined by cartilage and permit limited movement.

Synovial joints: Contain a synovial cavity filled with synovial fluid, allowing a wide range of movement.

Question 55

How synovial joints are adapted for movement and minimizing joint wear and tear

Answer 55

Synovial joints have articular cartilage to provide a smooth surface for joint movement and reduce friction.

The synovial membrane secretes synovial fluid, which lubricates the joint and nourishes the articular cartilage.

Ligaments and tendons provide stability and guide the movement of synovial joints.

Question 56

Major factors influencing tissue healing

Answer 56

Blood supply: Sufficient blood flow is crucial for delivering oxygen and nutrients to the healing area.

Severity of injury: The extent and depth of tissue damage affect the healing process.

Age and overall health: Younger individuals and those in good health generally have faster healing rates.

Infection and inflammation: Infection delays healing, while controlled inflammation is necessary for the healing process.

Treatment and management: Proper wound care, immobilization, and appropriate medical interventions can impact healing outcomes.

Question 57

List the types of pathogens that infect humans and appreciate how their size and structure is important in human infection

Answer 57

Bacteria: Single-celled organisms that can cause various infections.

Viruses: Tiny particles that invade host cells and use their machinery to replicate.

Fungi: Microscopic organisms that can cause infections in the skin, nails, or internal organs.

Parasites: Organisms that live on or inside a host and rely on them for survival.

Size: Pathogens vary in size, which affects their ability to enter and survive within the human body. Smaller pathogens like viruses can penetrate cells more easily.

Structure: Pathogens have unique structures that enable them to attach to host cells, evade the immune system, and cause damage. Understanding their structure helps in developing targeted treatments.

Question 58

Provide a broad overview of how the body defends itself against invaders

Answer 58

Non-specific defenses: These are the body’s first line of defense and include physical barriers (skin, mucous membranes), chemical barriers (enzymes, acid in the stomach), and inflammation.

Specific defenses: The immune system mounts specific responses to pathogens. It involves the recognition of antigens, activation of immune cells, and production of antibodies to neutralize and eliminate pathogens.

Question 59

Identify the body’s main non-specific and specific defence cells and their major functions

Answer 59

Phagocytes: Engulf and destroy pathogens. Examples include neutrophils and macrophages.

Natural killer cells: Destroy infected and cancerous cells.

Dendritic cells: Capture and present antigens to activate the immune response.

Question 60

Explain the processes of phagocytosis and list the body’s phagocytes and their roles in defence

Answer 60

Phagocytosis is the process by which phagocytes engulf and destroy pathogens.

Phagocytes include neutrophils, macrophages, and dendritic cells.

They recognize pathogens, adhere to them, and internalize them into a phagosome. The phagosome fuses with lysosomes to form a phagolysosome, where the pathogen is broken down.

Question 61

Describe the functions and features of the inflammatory response and how these can be detrimental in excess

Answer 61

Functions: Initiate immune response, recruit immune cells, increase blood flow, and promote tissue repair.

Features: Redness, heat, swelling, and pain at the site of inflammation.

Question 62

List the main antimicrobial substances of the body

Answer 62

Interferons: Proteins that inhibit viral replication and spread.

Complement proteins: Enhance immune response and aid in pathogen destruction.

Defensins: Small antimicrobial peptides that kill bacteria and fungi.

Question 63

Understand what is meant by the term antigen

Answer 63

Antigen is a molecule that can trigger an immune response.

It is recognized by the immune system as foreign, leading to the production of antibodies or activation of immune cells.

Question 64

Describe the features of antibodies and understand the key functions of each antibody class (IgM, IgA, IgD, IgG, IgE)

Answer 64

Antibodies are proteins produced by B cells in response to antigens.

MADGE

IgM: The first antibody produced during an immune response.

IgA: Found in body secretions and provides localized defense.

IgD: Helps activate B cells.

IgG: Most abundant antibody, provides long-term immunity.

IgE: Involved in allergic reactions and defense against parasites.

Question 65

Briefly describe the process of vaccination and how this contributes to immunity

Answer 65

Vaccination involves introducing weakened or killed pathogens or their antigens into the body to stimulate an immune response.

It allows the immune system to recognize and remember the pathogen, providing long-term immunity and protection against future infections.

Question 66

Describe the main features of the nervous system

Answer 66

The nervous system controls and coordinates body functions through electrical and chemical signals.

It consists of the brain, spinal cord, and peripheral nerves.

Question 67

Briefly describe how the nerve cell is adapted (it’s key features) to perform its job

Answer 67

Dendrites receive signals from other neurons.
The cell body contains the nucleus and organelles.

Axons transmit electrical signals away from the cell body.

Synaptic terminals transmit signals to other neurons or target cells.

Question 68

Understand the roles of myelin and synaptic transmission and their importance to communication in the nervous system

Answer 68

Myelin is a fatty substance that wraps around axons, speeding up the transmission of nerve impulses.

Synaptic transmission is the process by which signals are transmitted between neurons at synapses, allowing communication in the nervous system.

Question 69

Distinguish between the functions & composition of the central and peripheral nervous systems, and the somatic and autonomic nervous systems

Answer 69

Central nervous system (CNS): Includes the brain and spinal cord, responsible for processing and integrating information.
Peripheral nervous system (PNS): Consists of nerves that extend from the CNS to the rest of the body, transmitting signals.

Question 70

Describe the roles of the two divisions of the autonomic system

Answer 70

Somatic nervous system controls voluntary movements and sensory perception.

Autonomic nervous system regulates involuntary functions like heartbeat, digestion, and glandular activity.
Sympathetic division: Activated in response to stress, prepares the body for “fight or flight” response.
Parasympathetic division: Promotes relaxation and conserves energy, responsible for “rest and digest” functions.

Question 71

Explain the concept of homeostasis and how the body uses negative feedback loops to maintain homeostasis: appreciate the role that positive feedback loops have in the body

Answer 71

Homeostasis is the body’s ability to maintain stable internal conditions.
Negative feedback loops are regulatory mechanisms that reverse any deviation from the desired state, restoring homeostasis.

Question 72

Describe the role of the nervous system in maintaining homeostasis and begin to appreciate the similarities & differences to the role of the endocrine system in this process

Answer 72

The nervous system monitors and controls various body functions to maintain homeostasis. It receives and processes sensory information and initiates appropriate responses.

• The nervous system uses electrical signals for rapid communication, while the endocrine system uses hormones for slower but longer-lasting regulation.
• Both systems work together to maintain homeostasis, with the nervous system providing rapid responses and the endocrine system regulating long-term changes.

Question 73

Compare and contrast the nervous and endocrine systems and the way they control and coordinate body functions

Answer 73

Comparing and contrasting the nervous and endocrine systems:

Nervous System:
Communication: Uses electrical impulses and neurotransmitters for rapid communication.
Speed: Provides fast responses to stimuli.
Target: Specific target cells or organs.
Duration: Short-term effects.
Control: Controls voluntary and involuntary functions.

Endocrine System:
Communication: Uses hormones released into the bloodstream for communication.
Speed: Provides slower but longer-lasting responses.
Target: Distant target cells or organs.
Duration: Long-term effects.
Control: Controls various body functions through hormone secretion.

Question 74

Describe the purpose of positive and negative feedback loops, and give an example of each

Answer 74

Positive Feedback Loop: Amplifies or reinforces a response, moving away from the initial state. Example: Childbirth contractions, where each contraction stimulates more contractions until delivery.

Negative Feedback Loop: Stabilizes and returns the system to its original state, reversing the initial response. Example: Regulation of body temperature, where sweating cools the body and reduces temperature until it reaches normal levels.

Question 75

Describe the way in which hormones that require central nervous system input in their release are controlled

Answer 75

Hormones that require central nervous system input for release are regulated by signals from the hypothalamus.

The hypothalamus monitors various factors and initiates the release of hormones from the pituitary gland in response to these signals.

Question 76

Describe, in general terms, how the hypothalamus controls the release of hormones from the pituitary gland

Answer 76

The hypothalamus produces releasing and inhibiting hormones that travel to the anterior pituitary gland.

These hormones stimulate or inhibit the release of specific hormones from the anterior pituitary gland.

The hormones released by the anterior pituitary then target other endocrine glands to stimulate or inhibit their hormone production.

Question 77

Distinguish whether it is the endocrine gland, pituitary or hypothalamus that is functioning abnormally; by interpreting levels of
releasing (hypothalamic) and stimulating (anterior pituitary) hormones (and conversely identify what changes in hypothalamic, ant.pit. &
endocrine tissue hormones would occur when one of these tissues is malfunctioning)

Answer 77

If the hypothalamus is malfunctioning, there may be abnormal levels of releasing hormones.
If the anterior pituitary is malfunctioning, there may be abnormal levels of stimulating hormones.
If the endocrine gland is malfunctioning, there may be abnormal levels of the specific hormone produced by that gland.

Question 78

Match basic signs and symptoms of endocrine disorders with the functions of the hormones you have learnt, e.g. what hormone, when
present in excessive amounts, causes increased heart rate, weight loss, sweating, etc?

Answer 78

Increased heart rate, weight loss, and sweating can be associated with excessive amounts of thyroid hormones (hyperthyroidism).

Question 79

Give examples of physiological functions which require the nervous and endocrine systems to work together and explain why & how both are required for these functions

Answer 79

Stress response: The hypothalamus activates the release of hormones from the adrenal glands, coordinating the response between the two systems.

Regulation of metabolism: The thyroid hormones, under the control of the hypothalamus and pituitary, regulate metabolism and energy balance.

Question 80

Explain the major functions of all the hormones mentioned in the lecture

Answer 80

Thyroid hormones: Regulate metabolism, growth, and development.

Adrenal hormones (cortisol, adrenaline): Regulate stress response and metabolism.

Insulin: Regulates blood sugar levels.

Growth hormone: Stimulates growth and development.

Testosterone and estrogen: Regulate sexual development and reproductive functions.

Question 81

Describe how release of each hormone (mentioned in the lecture) is triggered and how its release is controlled

Answer 81

Hormone release can be triggered by various factors such as specific stimuli, changing levels of other hormones, or feedback mechanisms.

Hormone release is controlled by the hypothalamus and pituitary gland through a series of hormonal signals and feedback loops.

Question 82

Briefly describe the main events of meiosis, particularly the relevance of crossing over to genetic diversity and understand its relevance to reproduction

Answer 82

Meiosis is a type of cell division that produces haploid cells (gametes). It consists of two rounds of division (meiosis I and meiosis II). The main events include DNA replication, pairing of homologous chromosomes, crossing over (exchange of genetic material), separation of homologous chromosomes in meiosis I, and separation of sister chromatids in meiosis II. Meiosis results in the production of genetically diverse gametes.

Question 83

Describe the main structures of the female and male reproductive organs & the main functions of their sex hormones

Answer 83

Female: Ovaries (produce eggs), fallopian tubes (site of fertilization), uterus (womb for embryo development), cervix (entrance to uterus), and vagina (birth canal).
Estrogen (development of secondary sexual characteristics, regulation of menstrual cycle, maintenance of pregnancy) and progesterone (prepares uterus for pregnancy and maintains pregnancy).

Male: Testes (produce sperm), epididymis (stores and matures sperm), vas deferens (transports sperm), seminal vesicles, prostate gland, and bulbourethral glands (produce seminal fluid).
Testosterone (development of secondary sexual characteristics, sperm production, sex drive).

Question 84

Describe the processes occurring during the female reproductive cycle (ovarian & uterine) and how these are controlled and linked by hormones

Answer 84

Ovarian cycle: Follicular phase (development of follicles in the ovary), ovulation (release of egg), luteal phase (formation of corpus luteum).

Uterine cycle: Menstrual phase (shedding of uterine lining), proliferative phase (rebuilding of uterine lining), secretory phase (preparation of uterus for embryo implantation).

Question 85

Discuss the process of ovulation and the hormones that control it and the relevance of its timing to fertilisation and successful pregnancy

Answer 85

The release of a mature egg from the ovary. It is controlled by a surge in luteinizing hormone (LH) from the pituitary gland, triggered by high levels of estrogen. Timing of ovulation is crucial for successful fertilization and pregnancy.

Question 86

Outline the changes that occur in the female at puberty, including the physiology of menstruation

Answer 86

Puberty is the onset of sexual maturity. In females, it involves the development of breasts, growth of pubic hair, and the onset of menstruation (shedding of uterine lining). Menstruation occurs approximately every 28 days and is regulated by hormonal fluctuations.

Question 87

Briefly describe the structure and function of the female breast, particularly as it relates to lactation

Answer 87

The breast consists of glandular tissue, ducts, and fatty tissue. It produces milk during lactation to nourish an infant.

Question 88

describe the process of sperm production in the testes

Answer 88

Occurs in the seminiferous tubules. Immature sperm cells undergo mitotic division (spermatogonia), followed by meiotic division (spermatocytes), and differentiation into sperm cells (spermatids). Sperm cells are then released into the epididymis for maturation.

Question 89

Describe the secretions that pass into the semen

Answer 89

Seminal vesicles, prostate gland, and bulbourethral glands contribute fluids to semen. These fluids provide nourishment, buffer acidic environments, and enhance sperm motility.

Question 90

List the main developmental processes that occur during the three trimesters of pregnancy

Question 91

Briefly describe the main events occurring in the first trimester of pregnancy, the role of hCG and why teratogens are a problem

Answer 91

First trimester: Fertilization, implantation of embryo in the uterus, development of major organs and body systems, formation of placenta.

- Role of hCG: hCG is crucial in maintaining pregnancy during the first trimester. It signals the corpus luteum (a temporary gland formed after ovulation) to continue producing progesterone, which is essential for maintaining the uterine lining and supporting the pregnancy until the placenta fully forms and takes over hormone production. hCG is also the hormone detected in pregnancy tests.

Teratogens: Teratogens are substances or factors that can cause abnormalities or malformations in the developing fetus. During the first trimester, the embryo is particularly vulnerable to teratogens because this is when organogenesis occurs. Exposure to teratogens, such as certain medications, alcohol, drugs, infections, or radiation, can interfere with normal development and increase the risk of birth defects or pregnancy complications. It is crucial for pregnant individuals to avoid exposure to known teratogens to ensure the healthy development of the fetus.

Question 92

Describe the effects of pregnancy on maternal physiology

Answer 92

Pregnancy involves hormonal changes, increased blood volume, changes in heart and lung function, weight gain, and adaptations in the reproductive system to support fetal growth and development.

Question 93

Explain how labour is initiated and describe the three stages of labour

Answer 93

Labor is initiated by hormonal signals, including an increase in oxytocin. The stages of labor include dilation and effacement of the cervix, delivery of the baby, and delivery of the placenta.

Question 94

List the main causes of male and female infertility

Answer 94

Male factors include low sperm count, abnormal sperm function, or blockages in the reproductive tract.

Female factors include ovulation disorders, fallopian tube blockage, or problems with the uterus or cervix

Question 95

Briefly describe some techniques of assisted reproductive technology, including IVF and ICSI and understand how these are used in different situations

Answer 95

Techniques like in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) are used to overcome fertility issues.

IVF involves fertilizing eggs outside the body and transferring embryos to the uterus.

ICSI involves injecting a single sperm into an egg. These techniques are used in various situations, such as male infertility, fallopian tube damage, or unexplained infertility.

Question 96

Briefly describe, in broad terms, the general arrangement and purpose of the cardiovascular system

Answer 96

The cardiovascular system consists of the heart, blood vessels, and blood. Its purpose is to transport oxygen, nutrients, hormones, and waste products throughout the body

Question 97

Explain why the heart is described as a “double pump” and how the pumps work synchronously to supply blood to the pulmonary and systemic circuits

Answer 97

The heart is described as a “double pump” because it has two sides: the right side pumps oxygen-poor blood to the lungs for oxygenation (pulmonary circulation), and the left side pumps oxygen-rich blood to the rest of the body (systemic circulation). These pumps work synchronously to ensure a continuous flow of blood through the two circuits.

Question 98

Briefly describe the main characteristics of arteries, arterioles, capillaries and veins, and how their structure underlies their main functions

Answer 98

Arteries are thick-walled blood vessels that carry oxygenated blood away from the heart. Arterioles are smaller branches of arteries that regulate blood flow to specific areas. Capillaries are tiny, thin-walled vessels where the exchange of nutrients, gases, and waste products occurs between the blood and tissues. Veins are blood vessels that carry deoxygenated blood back to the heart. Their structure, such as the presence of smooth muscle and valves, supports their functions of carrying and regulating blood flow.

Question 99

Explain briefly how exchange of nutrients, gases and wastes occur between the blood and the tissues

Answer 99

Exchange of nutrients, gases, and wastes between the blood and tissues occurs through the process of diffusion across the walls of capillaries. Oxygen and nutrients diffuse from the capillaries into the tissues, while carbon dioxide and waste products diffuse from the tissues into the capillaries.

Question 100

Describe the path blood takes through the chambers and valves of the heart and the major blood vessels transporting blood in and out of the heart

Answer 100

Blood enters the heart through the superior and inferior vena cava, filling the right atrium. From there, it passes through the tricuspid valve into the right ventricle. The right ventricle then pumps blood through the pulmonary valve into the pulmonary artery, which carries it to the lungs for oxygenation. Oxygenated blood returns to the heart through the pulmonary veins, entering the left atrium. It then flows through the mitral valve into the left ventricle, which pumps blood through the aortic valve into the aorta, the main artery that distributes blood to the rest of the body.

Question 101

Relate the closure and opening of valves in the heart and major vessels to the flow of blood during diastole and systole

Answer 101

The closure and opening of valves in the heart and major vessels occur during diastole and systole. During diastole (relaxation phase), the atrioventricular valves (tricuspid and mitral valves) open to allow blood to flow from the atria to the ventricles. During systole (contraction phase), the ventricles contract, closing the atrioventricular valves to prevent backflow, and the semilunar valves (pulmonary and aortic valves) open to allow blood to be ejected from the heart.

Question 102

Explain why the electrical activation of the heart has to occur in a precisely timed sequence, and relate the electrical activation and deactivation of the heart muscle to the components of the ECG

Answer 102

The electrical activation of the heart occurs in a precisely timed sequence to ensure coordinated and efficient contractions. The electrical signals initiate from the sinoatrial (SA) node, the heart’s natural pacemaker, and travel through the atria and ventricles, causing them to contract. This electrical activity can be measured by an electrocardiogram (ECG), which records the depolarization and repolarization of the heart muscle.

Question 103

Explain the difference between systolic, diastolic and mean arterial pressure (MAP)

Answer 103

Systolic pressure refers to the maximum pressure exerted on the arterial walls during ventricular contraction, while diastolic pressure is the minimum pressure when the ventricles are relaxed. Mean arterial pressure (MAP) is the average pressure in the arteries during one cardiac cycle and is calculated using the formula MAP = diastolic pressure + (pulse pressure/3). Pulse pressure is the difference between systolic and diastolic pressure.

Question 104

Describe the two main systems for controlling blood pressure (nervous and endocrine), and the mechanisms by which each system brings about increases and decreases in pressure

Answer 104

The two main systems for controlling blood pressure are the nervous system and the endocrine system. The nervous system regulates blood pressure through the autonomic nervous system, specifically the sympathetic and parasympathetic divisions. The sympathetic division increases blood pressure, while the parasympathetic division decreases it. The endocrine system regulates blood pressure through hormones such as aldosterone and antidiuretic hormone, which affect fluid balance and blood vessel constriction.

Question 105

Apply your knowledge of the basic function of the cardiovascular system to what happens when parts of the system fail in various disease states

Answer 105

When parts of the cardiovascular system fail, it can lead to various disease states. For example, a blockage in the coronary arteries can result in a heart attack, where blood flow to the heart muscle is restricted. Hypertension (high blood pressure) can strain the blood vessels and increase the risk of heart disease and stroke. Heart valve disorders can lead to impaired blood flow. Understanding these failures helps in diagnosing and treating cardiovascular diseases.

Question 106

List the broad functions of the respiratory system

Answer 106

Gas exchange: Facilitating the exchange of oxygen and carbon dioxide between the body and the environment.

Oxygenation: Supplying oxygen to the body’s cells for cellular respiration and energy production.

Removal of carbon dioxide: Removing carbon dioxide, a waste product of cellular respiration, from the body.

pH regulation: Maintaining the acid-base balance in the body through the regulation of carbon dioxide levels.

Question 107

Describe the functions of the three major parts of the respiratory system, and how the structure of these parts reflects their functions

Answer 107

The three major parts of the respiratory system are the airways (nose, mouth, pharynx, larynx, trachea, bronchi, bronchioles), the lungs (alveoli), and the respiratory muscles (diaphragm and intercostal muscles). The structure of these parts reflects their functions. For example, the airways have a branching structure that helps in the filtration, humidification, and warming of incoming air. The alveoli have a thin, moist, and highly vascularized structure, enabling efficient gas exchange between the air and bloodstream. The respiratory muscles, particularly the diaphragm, facilitate the expansion and contraction of the lungs during breathing.

Question 108

Briefly explain what the term partial pressure means

Answer 108

Partial pressure refers to the pressure exerted by an individual gas within a mixture of gases. In the context of respiration, it refers to the pressure exerted by oxygen and carbon dioxide within the air or blood. The partial pressure of a gas determines the direction and rate of its diffusion across membranes.

Question 109

Describe how the pleura and the muscles of respiration operate in inspiration and expiration, and what can cause this function to be compromised

Answer 109

During inspiration, the diaphragm and intercostal muscles contract, causing the chest cavity to expand. This expansion lowers the pressure in the lungs, allowing air to flow in. Expiration occurs when the diaphragm and intercostal muscles relax, causing the chest cavity to decrease in size. This increases the pressure in the lungs, forcing air to be expelled. Compromises to these functions can occur due to conditions such as respiratory muscle weakness, chest wall abnormalities, or neurological disorders.

Question 110

Describe the factors that contribute to expiration and how these are affected by the disease states discussed

Answer 110

Factors contributing to expiration include the elastic recoil of the lungs, relaxation of respiratory muscles, and increased intra-abdominal pressure. Disease states like chronic obstructive pulmonary disease (COPD) can impair expiration by causing airway obstruction and reducing lung elasticity.

Question 111

Describe how gases are exchanged across the alveolar wall, and what can cause this process to be compromised

Answer 111

Gas exchange across the alveolar wall occurs through diffusion. Oxygen from the alveoli diffuses into the bloodstream, while carbon dioxide from the bloodstream diffuses into the alveoli. This process can be compromised by conditions such as pulmonary oedema, pneumonia, or fibrosis, which thicken the alveolar walls and impair gas exchange.

Question 112

Describe the transport of oxygen and carbon dioxide in the blood, and how this transport ensures adequate delivery of oxygen to tissues

Answer 112

Oxygen is primarily transported in the blood bound to haemoglobin, forming oxyhemoglobin. Carbon dioxide is transported in the blood in three forms: dissolved in plasma, as bicarbonate ions, and bound to haemoglobin. This transport mechanism ensures the adequate delivery of oxygen to tissues and the removal of carbon dioxide from the body.

Question 113

Explain how the rate and depth of breathing is controlled, and the factors which may alter it

Answer 113

The rate and depth of breathing are controlled by the respiratory centres in the brainstem, primarily influenced by the levels of carbon dioxide, oxygen, and pH in the blood. Factors such as exercise, emotions, and respiratory diseases can alter the breathing rate and depth.

Question 114

Describe the defence mechanisms for the respiratory tract

Answer 114

The respiratory tract has defence mechanisms to protect against pathogens and foreign particles. These include the production of mucus, the presence of cilia that sweep mucus and trapped particles out of the airways, and immune cells that help eliminate pathogens.

Question 115

List the lung volumes and measurements which are commonly used to identify respiratory disorders and explain how and why these volumes are affected by disease processes

Answer 115

Lung volumes and measurements commonly used to identify respiratory disorders include tidal volume, inspiratory reserve volume, expiratory reserve volume, vital capacity, forced expiratory volume, and peak expiratory flow rate. These measurements provide information about lung function, airway obstruction, and the presence of respiratory disorders. Disease processes can affect these volumes by reducing lung capacity, causing airway obstruction, or impairing gas exchange.

Question 116

Briefly describe the body’s nutritional requirements that can be obtained from food

Answer 116

The body’s nutritional requirements that can be obtained from food include macronutrients (carbohydrates, proteins, and fats) for energy production and building blocks for cellular structures, micronutrients (vitamins and minerals) for various metabolic processes, fibre for digestive health, and water for hydration and bodily functions.

Question 117

Identify the main organs of the gastrointestinal tract (GIT) and their major functions

Answer 117

• Mouth: Begins the process of mechanical digestion through chewing and initiates chemical digestion through the secretion of saliva.
• Oesophagus: Transports food from the mouth to the stomach through peristalsis.
• Stomach: Stores and mixes food, secretes gastric juices for chemical digestion, and partially digests proteins.
• Small intestine: Completes digestion of carbohydrates, proteins, and fats, and absorbs nutrients into the bloodstream.
• Large intestine: Absorbs water, electrolytes, and vitamins, and forms and eliminates faeces.

Question 118

List the accessory organs of digestion
The accessory organs of digestion include the liver, pancreas, and gallbladder.

Answer 118

• Liver: Produces bile for the emulsification and digestion of fats, detoxifies harmful substances, and stores nutrients.
  
  • Pancreas: Produces digestive enzymes to break down carbohydrates, proteins, and fats in the small intestine, and secretes bicarbonate to neutralize stomach acid.
  • Gallbladder: Stores and concentrates bile produced by the liver, releasing it into the small intestine to aid in fat digestion.

Question 119

Explain the function of smooth muscle in the walls of the GIT including the different types of motility this can achieve

Answer 119

Smooth muscle in the walls of the gastrointestinal tract allows for different types of motility, including peristalsis (wave-like contractions) for propelling food forward, segmentation for mixing and churning food, and tonic contractions for maintaining pressure and tone in the digestive tract.

Question 120

Explain the role of the mouth and saliva in digestion

Answer 120

The mouth and saliva play a role in digestion by mechanically breaking down food through chewing and moistening it for easier swallowing. Saliva contains enzymes, such as amylase, that begin the chemical digestion of carbohydrates.

Question 121

Briefly describe the process of swallowing and the role of the oesophagus

Answer 121

Swallowing, or deglutition, involves the coordinated movement of the tongue, soft palate, pharynx, and oesophagus to propel food from the mouth to the stomach. The oesophagus serves as a conduit for food, using peristalsis to transport it to the stomach.

Question 122

Discuss the structure and digestive functions of the stomach

Answer 122

The stomach has muscular walls that contract and relax to mix and churn food with gastric juices, including hydrochloric acid and enzymes such as pepsin, to break down proteins. The stomach also secretes mucus to protect its lining from acid and provide lubrication.

Question 123

Describe the ways in which hormones and nervous system activities regulate the action of the GIT

Answer 123

Hormones and nervous system activities regulate the action of the gastrointestinal tract. Hormones, such as gastrin and secretin, stimulate the release of digestive juices and regulate gastric emptying. The nervous system, particularly the vagus nerve, controls digestive processes by stimulating or inhibiting the release of digestive enzymes and regulating smooth muscle contractions.

Question 124

Discuss the digestive functions of the small intestine and its secretions

Answer 124

The small intestine is the primary site of digestion and absorption. It receives secretions from the liver and pancreas, which provide enzymes and bicarbonate for digestion. The small intestine has specialized structures called villi and microvilli that increase the surface area for nutrient absorption.

Question 125

Explain broadly how nutrients are absorbed in the small intestine

Answer 125

Nutrients are absorbed in the small intestine through various mechanisms. Carbohydrates are broken down into simple sugars and absorbed as glucose, proteins are broken down into amino acids and absorbed, and fats are broken down into fatty acids and monoglycerides and absorbed as micelles. Nutrients are transported across the intestinal epithelium into the bloodstream or lymphatic system.

Question 126

Describe the structure and functions of the large intestine

Answer 126

The large intestine absorbs water, electrolytes, and some vitamins produced by gut bacteria. It also helps form and eliminate faeces through the process of peristalsis.

Question 127

Differentiate between the functions of the exocrine and endocrine pancreas & explain the digestive actions of its exocrine secretions

Answer 127

The exocrine pancreas produces digestive enzymes, including amylase, proteases, and lipases, which are activated in the small intestine. These enzymes break down carbohydrates, proteins, and fats into smaller molecules for absorption.

Question 128

List the functions of the liver

Answer 128

The liver has multiple functions, including the production of bile, detoxification of harmful substances, metabolism of nutrients, storage of glycogen, synthesis of plasma proteins, and regulation of cholesterol and lipid metabolism.

Question 129

Outline the structure and functions of the gall bladder

Answer 129

The gallbladder stores and concentrates bile produced by the liver. When stimulated by the hormone cholecystokinin, the gallbladder contracts and releases bile into the small intestine to aid in the digestion and absorption of fats.

Question 130

List the principal digestive enzymes, their sites of action, how they are activated, their substrates and their products

Answer 130

The principal digestive enzymes include amylase (breaks down carbohydrates), proteases (break down proteins), and lipases (break down fats). These enzymes act at specific sites in the digestive system, such as the mouth, stomach, and small intestine, and are activated by optimal pH conditions and cofactors.

Question 131

Describe the sites of absorption of the main nutrient groups

Answer 131

• The main nutrient groups are absorbed at specific sites in the small intestine:
  
  • Carbohydrates are absorbed as glucose in the jejunum.
  • Proteins are absorbed as amino acids in the jejunum.
  • Fats are absorbed as fatty acids and monoglycerides in the duodenum and jejunum.

Question 132

Discuss general principles of metabolism, including anabolism, catabolism, units of energy and metabolic rate

Answer 132

Metabolism refers to the chemical processes that occur within cells to maintain life. Anabolism involves building complex molecules from simpler ones, while catabolism involves breaking down complex molecules into simpler ones. The units of energy in metabolism are ATP (adenosine triphosphate), which is produced through the breakdown of nutrients.

Question 133

Compare and contrast the metabolic fate of the body’s main energy sources (carbohydrate, protein and fat) & briefly describe the processes that these sources can undergo (e.g. gluconeogenesis)

Answer 133

Carbohydrates, proteins, and fats can undergo different processes for energy production. Carbohydrates can be converted into glucose through processes like gluconeogenesis. Proteins can be broken down into amino acids, which can be used for energy or converted into glucose or fatty acids. Fats can be oxidized to produce ATP through beta-oxidation.

Question 134

Briefly describe how cells use sugars, fats and protein to make ATP

Answer 134

Cells use sugars, fats, and proteins to make ATP through cellular respiration. Glucose from sugars is broken down through glycolysis and the citric acid cycle, producing ATP and releasing carbon dioxide as a waste product. Fatty acids from fats are broken down through beta-oxidation to generate ATP. Proteins can be converted into intermediates of glycolysis or the citric acid cycle for ATP production.

Question 135

Explain the ways in which failure in the normal function of the GIT or accessory organs can affect digestion and metabolism

Answer 135

Failure in the normal function of the gastrointestinal tract or accessory organs can affect digestion and metabolism. Conditions such as gastrointestinal disorders, liver disease, and pancreatic dysfunction can impair the production and release of digestive enzymes, absorption of nutrients, and metabolism of carbohydrates, proteins, and fats.

Question 136

Describe the health risks produced by obesity, and the factors influencing the development of obesity, including the hormones involved in regulating satiety & feeding

Answer 136

Obesity poses health risks, including an increased risk of cardiovascular disease, type 2 diabetes, certain cancers, and musculoskeletal disorders.

Factors influencing the development of obesity include genetic predisposition, sedentary lifestyle, excessive caloric intake, hormonal imbalances (e.g., leptin resistance), and psychological factors.

Hormones involved in regulating satiety and feeding include leptin, ghrelin, and insulin.

Question 137

Name the major structures of the urinary system

Answer 137

The major structures of the urinary system include the kidneys, ureters, bladder, and urethra.

Question 138

List the functions of the kidneys, and describe (in the degree of detail covered in this week’s lecture and relevant previous lectures eg. endocrine) how the kidney performs each of these

Answer 138

Functions of the kidneys: BED WAVE
1. Blood pressure regulation: The kidneys play a role in regulating blood pressure through the renin-angiotensin-aldosterone system.

2. Electrolyte balance and fluid: The kidneys maintain the balance of water and electrolytes (sodium, potassium, calcium, etc.) in the body by adjusting their reabsorption and excretion. The kidneys selectively reabsorb essential substances, such as water, glucose, amino acids, and ions, from the filtrate back into the bloodstream.
3. Drug Metabolisim Secretion: The kidneys secrete substances, such as hydrogen ions and certain drugs, from the bloodstream into the filtrate to be excreted.
4. Waste elimination and filtration: The kidneys filter blood to remove waste products, toxins, and excess substances while retaining necessary molecules.
5. Acid-base balance: The kidneys regulate the pH of body fluids by controlling the excretion of hydrogen ions and the reabsorption of bicarbonate ions.
6. Vitamin D activation: The kidneys convert inactive vitamin D into its active form, which is important for calcium absorption and bone health.
7. Erythropoietin: secretion of the hormone erythropoietin

Question 139

Describe (in the degree of detail covered in lectures) how the kidney tubule produces urine and how it alters the composition of urine to maintain Homeostasis

Answer 139

The kidney tubule produces urine through several processes:
1. Filtration: Blood enters the glomerulus, and pressure forces water, ions, and small molecules out of the glomerular capillaries into the Bowman’s capsule, forming the filtrate.
2. Reabsorption: As the filtrate flows through the renal tubules, essential substances like glucose, amino acids, and ions are actively reabsorbed back into the bloodstream.
3. Secretion: Certain substances, such as hydrogen ions and drugs, are actively secreted from the bloodstream into the tubules to be eliminated in urine.
4. Concentration and dilution: The tubules adjust the concentration of urine by reabsorbing water and ions based on the body’s hydration status and needs.
5. pH regulation: The tubules secrete hydrogen ions and reabsorb bicarbonate ions to regulate the pH of urine and maintain acid-base balance.

Question 140

Explain how the respiratory system, the kidneys and the buffer systems work together to maintain body fluid pH homeostasis

Answer 140

The respiratory system, kidneys, and buffer systems work together to maintain body fluid pH homeostasis. The respiratory system regulates the levels of carbon dioxide and acid by adjusting the rate and depth of breathing. Carbon dioxide combines with water in the blood, forming carbonic acid, which can be buffered by bicarbonate ions. The kidneys help regulate pH by reabsorbing bicarbonate ions and excreting hydrogen ions. Buffer systems, such as the bicarbonate buffer system, act as chemical buffers in the blood, minimizing changes in pH by accepting or donating hydrogen ions.

Question 141

Explain the consequences of protein loss in the urine in terms of fluid shifts

Answer 141

Protein loss in the urine, known as proteinuria, can lead to fluid shifts and oedema (swelling). Proteins help maintain the osmotic balance between blood vessels and tissues. When proteins are lost in urine, there is reduced oncotic pressure in the blood vessels, causing fluid to shift from the blood vessels into the interstitial spaces, leading to oedema.

Question 142

Using your knowledge of the functions of the kidneys, explain and predict the consequences of kidney failure including disruption to the filtration apparatus of the kidney

Answer 142

Kidney failure can have various consequences due to the disruption of the filtration apparatus:
1. Accumulation of waste products and toxins in the blood, leading to uraemia.

2. Fluid and electrolyte imbalances, causing oedema or dehydration and electrolyte abnormalities.
3. Acid-base imbalances, as the kidneys are unable to regulate pH properly.
4. Anaemia due to decreased production of erythropoietin, leading to reduced red blood cell production
5. Bone and mineral disorders, as the kidneys are unable to activate vitamin D properly, leading to calcium and phosphate imbalances.
6. Hypertension, as the impaired regulation of blood pressure can occur in kidney failure.
7. Decreased urine production and oliguria or anuria (absence of urine output).