Endocrine and Muscle Physiology Quiz

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Questions and Answers

What is the primary trigger for smooth muscle contraction?

Increase in intracellular sodium

Increase in intracellular calcium (correct)

Decrease in extracellular potassium

Increase in ATP concentration

Which structure is essential for electrical coupling between smooth muscle fibers?

Gap junctions (correct)

Hemidesmosomes

Intercalated discs

T-tubules

How do pacemaker cells contribute to heart muscle contraction?

They inhibit calcium channels to reduce contraction.

They generate action potentials that trigger contraction. (correct)

They release neurotransmitters to stimulate cardiac neurons.

They synchronize contractions through ATP consumption.

What effect does sympathetic stimulation have on heart rate?

It increases heart rate. Signup and view all the answers

Which chemical factors can spontaneously depolarize smooth muscle lacking nerve supply?

Increased carbon dioxide and low pH Signup and view all the answers

What is the primary role of growth hormone (GH) in metabolism?

Mobilizes fat from fat depots Signup and view all the answers

Which hormone is primarily responsible for stimulating the adrenal cortex?

Adrenocorticotropic hormone Signup and view all the answers

What triggers the release of thyroid stimulating hormone (TSH)?

Thyrotropin-releasing hormone Signup and view all the answers

How does growth hormone influence growth indirectly?

Stimulates insulin-like growth factors Signup and view all the answers

What feedback mechanism regulates the secretion of growth hormone?

Negative feedback by GH and IGF Signup and view all the answers

Which of the following hormones primarily stimulates milk production?

Prolactin Signup and view all the answers

What is the function of follicle-stimulating hormone (FSH) in the reproductive system?

Stimulates the production of gametes Signup and view all the answers

What effect do rising levels of glucocorticoids have on corticotropin-releasing hormone (CRH) secretion?

Inhibit CRH secretion Signup and view all the answers

Which of the following correctly defines phagocytosis?

The ingestion of solid materials by a cell Signup and view all the answers

What is the primary consequence of leucopenia?

Abnormally low white blood cell count Signup and view all the answers

How are leukemias categorized?

Based on the type of leukocyte involved Signup and view all the answers

What initiates a vascular spasm during haemostasis?

Direct injury to vascular smooth muscle cells Signup and view all the answers

What role does Von Willebrand Factor play in platelet plug formation?

Stabilizes bound platelets to collagen Signup and view all the answers

Which of the following is NOT a characteristic of agranulocytes?

Presence of visible cytoplasmic granules Signup and view all the answers

What substances are primarily involved in regulating leucopoiesis?

Interleukins and colony-stimulating factors Signup and view all the answers

What triggers the release of ADP during platelet plug formation?

Activation of platelets upon adhering to collagen Signup and view all the answers

What happens during depolarization of a neuron?

Na^+ channels open and cell interior becomes less negative Signup and view all the answers

Which factor increases the rate of action potential propagation in an axon?

Increased diameter of the axon Signup and view all the answers

What distinguishes excitatory postsynaptic potentials (EPSP) from inhibitory postsynaptic potentials (IPSP)?

EPSP causes local depolarization, while IPSP causes local hyperpolarization Signup and view all the answers

Which type of summation occurs when multiple presynaptic neurons stimulate a postsynaptic neuron simultaneously?

Spatial summation Signup and view all the answers

What are neurotransmitters primarily responsible for in the nervous system?

Transmitting information between neurons and effectors Signup and view all the answers

In the brain, which region is responsible for the conscious control of precise voluntary movements?

Primary motor cortex Signup and view all the answers

What does the anterior association area, also known as the prefrontal cortex, primarily govern?

Intellect, complex learning abilities, and personality Signup and view all the answers

What role do chemically-gated channels play in postsynaptic potentials?

They determine whether the postsynaptic neuron is excited or inhibited Signup and view all the answers

Which type of matter primarily consists of myelinated axons in the brain?

White matter Signup and view all the answers

Which of the following neurotransmitters is considered a biogenic amine?

Serotonin Signup and view all the answers

What is the net gain of ATP molecules per glucose molecule during glycolysis?

2 ATP molecules Signup and view all the answers

Which molecule is produced when lactic acid is oxidized back?

Pyruvic acid Signup and view all the answers

In which cellular compartment does the citric acid cycle occur?

Mitochondrial matrix Signup and view all the answers

Which of the following is NOT a product of each turn of the citric acid cycle?

2 pyruvic acid molecules Signup and view all the answers

What role do reduced coenzymes play in the electron transport chain?

They act as substrates. Signup and view all the answers

What is the primary function of the electron transport chain?

To generate ATP from the energy of electrons. Signup and view all the answers

During the transitional phase of metabolism, which molecule is pyruvic acid converted into?

Acetyl CoA Signup and view all the answers

What happens to NADH + H+ when oxygen is available?

It delivers hydrogen atoms to the electron transport chain. Signup and view all the answers

What is the primary role of vitamin K in the coagulation process?

Synthesizes clotting factors Signup and view all the answers

Which condition is characterized by undesirable clot formation in an unbroken blood vessel?

Thrombus Signup and view all the answers

What triggers the process of fibrinolysis?

Activation of plasminogen Signup and view all the answers

What are the main components that contribute to the formation of a platelet plug?

Platelets and fibrin threads Signup and view all the answers

Which of the following blood groups is characterized by the absence of A and B agglutinogens?

O blood group Signup and view all the answers

What is the role of platelet-derived growth factor (PDGF) in clot retraction?

Stimulates fibroblast division Signup and view all the answers

Which gas law explains the solubility of a gas in a liquid based on its partial pressure?

Henry's law Signup and view all the answers

What defines external respiration in the respiratory process?

Diffusion of gases between lungs and blood Signup and view all the answers

Which is a hereditary bleeding disorder characterized by a deficiency of clotting factors?

Haemophilia Signup and view all the answers

What is the main function of the conducting zone of the respiratory system?

Air filtering and warming Signup and view all the answers

Which substance is primarily responsible for the transport of oxygen in the blood?

Hemoglobin Signup and view all the answers

What process is described as the sum of all biochemical reactions in the body?

Metabolism Signup and view all the answers

What causes the formation of agglutinins in the blood plasma?

Absence of specific antigens Signup and view all the answers

What is the primary structural characteristic of the alveolar walls involved in gas exchange?

Single layer of squamous epithelial cells Signup and view all the answers

Study Notes

Organic Molecules

Organic molecules are the building blocks of life
Carbohydrates are a readily available energy source for the body.
General structure: Carbon : 2 * Hydrogen : Oxygen
Monosaccharides are single-chain or single-ring structures, with pentose (5 carbon) and hexose (6 carbon) sugars being the most important in the body.
Disaccharides form when two monosaccharides join via dehydration synthesis
Polysaccharides are large, insoluble molecules, ideal for storage. Starch is a plant storage carbohydrate, and glycogen is an animal storage carbohydrate.
Lipids insulate body organs, build cell membranes, and provide stored energy.
Triglycerides are made of 1 glycerol and 3 fatty acids.
Phospholipids have a phosphate-containing group, and are a chief component of cell membranes.
Steroids are flat molecules with interlocking 4 hydrocarbon rings.

Proteins

Proteins are the body's primary structural material and have many functions.
The primary protein structure is a linear sequence of amino acids.
Secondary protein structures include alpha-helix and beta-sheet.
Tertiary structure: when secondary structures fold upon one another to produce a ball-like globular structure.
Quaternary structure: proteins that consist of more than one polypeptide chain.
Types of proteins include fibrous proteins (structural support) and globular proteins (functional).
Example fibrous proteins include collagen.
Globular proteins include enzymes that help regulate biochemical reactions.

Cells

Cells are the fundamental structural and functional units of living organisms.
Plasma membrane: the outer boundary of the cell, acting as a selective barrier.
Phospholipid layer: Forms the basic structure of the membrane, with hydrophilic heads facing the water and hydrophobic tails facing away from the water.
Membrane proteins: some are constitutive (part of the membrane) while others are inducible (moving/changing positions)
Cytoplasm: the intracellular fluid containing organelles.
Nucleus: controls cellular activities; encloses chromatin (genetic information).
Mitochondria: a powerplant; double membrane, with own DNA; contains ribosomes.
Ribosomes: involved in protein synthesis. Some are bound to the ER to synthesize proteins to be secreted, and others are free in the cytosol.
Endoplasmic Reticulum: network of membranes
Rough ER: associated with ribosomes, important for protein synthesis
Smooth ER: no ribosomes, involved in lipid metabolism, steroid hormone synthesis, drug detoxification
Golgi apparatus: processes, packages, and ships proteins and lipids.
Lysosomes: Contain digestive enzymes, essential for breaking down material.
Cytoskeleton: Network of rods & accessory proteins that provides the cell with support and shape.
Centrosome & centrioles: cell center that help in cell division
Extracellular material: substances outside cells that contribute to body mass (e.g., body fluids, cellular secretions, extracellular matrix)
Cell junctions: Structures that connect cells (e.g., tight junctions, desmosomes, gap junctions).

Cell Cycle

Cell cycle = period of cell formation to cell division. Involves three substages (G1, S, G2), followed by mitosis (prophase, metaphase, anaphase and telophase) and cytokinesis.

DNA (Deoxyribonucleic Acid)

Nucleotide is the basic unit of DNA
DNA is a double-helix molecule consisting of paired bases (adenine-thymine, guanine-cytosine).
DNA replication involves copying the DNA molecule to create two identical copies of a DNA molecule.

Transcription & Translation

Transcription is the process by which the information encoded in DNA is copied into a molecule of RNA -> messengerRNA(mRNA).
mRNA leaves the nucleus and travel to ribosomes -> Translation
Translation is the process in which mRNA is used to create protein. The transfer RNA(tRNA) molecules carry amino acids to the ribosomes, where they are assembled according to the sequence of codons in mRNA.
Initiaton: tRNA subunit binds to mRNA to produce a functional ribosome.
Elongation: rRNA/mRNA complex move along
Termination: end codon is reached, water is added to break the peptide chain, and the polypeptide is released.

Tissues

Tissues are groups of cells that are similar in structure and function.
Epithelial tissue covers body surfaces and lines cavities.
Connective tissue supports, connects, and separates different tissues. It is made of ground substance (cellular matrix) and connective tissue fibers and cells.
Muscle tissue is responsible for movement.
Nervous tissue is responsible for communication. It is composed of neurons that transmit impulses and neuroglia that support the neurons.

Human development

Spermatogenesis: produces male gametes (sperm).
Oogenesis: produces female gametes (ova). Involves meiosis -> one ovum with 23 chromosomes.
Meiosis: type of cell division -> reductional division.
Fertilization: joins a sperm to an ovum to form a zygote (initiating embryonic development)

Embryonic development.

Stages include cleavage (multiple mitotic divisions)
Blastocyst formation
Implantation in the uterus
Gastrulation

Covering, Support and Movement of the Body

The integumentary system consists of skin, hair and nails.
Epidermis: outermost protective layer
Dermis: beneath epidermis, contains connective tissue, including nerve endings.
Hypodermis: fatty tissue that anchors skin to underlying tissue.
Bone tissue is connective tissue that forms a skeleton.
Hyaline, elastic and fibrocartilage are different types of cartilage.
Bones are organ structures, composed of different tissue types (e.g., compact bone, spongy bone).
Skeletal muscles are responsible for body movements.

Muscles and Muscle Tissues

Muscle tissues contain specialized muscle cells (muscle fibers) that contract to cause body motion.
Types include skeletal muscles (voluntary), cardiac muscles (involuntary) and smooth muscles (involuntary).
Muscle fibers contain myofibrils which are organized into repeating units called sarcomeres.
Basic components include sarcomeres, A bands, H zones and M lines, I bands, Z discs and myofilaments.
Myofilaments include thick (myosin) and thin (actin) filaments whose relative positions change to cause contraction
Sliding filament model: Mechanism of skeletal muscle contraction, based on the sliding of thin filaments (actin) past thick filaments (myosin) to shorten the sarcomere.

Regulation and Integration of the Body

The nervous system is divided into two components – Central nervous system (CNS) and Peripheral Nervous system (PNS).
Neurons are specialized cells that transmit electrical signals.
Neuroglia are support cells
Types include astrocytes; microglia; ependymal cells; oligodendrocytes; satellite cells and schwann cells.
Different types of neurons include sensory (afferent); motor (efferent); and interneurons.
Different neurotransmitters carry signals between neurons.
The human brain is divided into four major areas – cerebral hemispheres, diencephalon, brainstem and cerebellum.
Cerebral cortex is the outermost layer of the cerebral hemispheres. Includes primary and association areas.

The Respiratory System

The respiratory system's main function is to facilitate gas exchange.
The respiratory system's organs include the nose, pharynx, larynx, trachea, bronchi and lungs (alveoli).
Different respiratory structures ensure the air's warming and filtration, as well as voice production.

The Cardiovascular System

The cardiovascular system circulates blood to deliver oxygen and nutrients and carry waste away.
The heart is a four chambered pump driving blood flow.
Blood vessels include arteries, veins, capillaries.

The Digestive System

Intake, propulsion, digestion & absorption, defecation are major functions of the digestive system.
Main parts include the mouth, pharynx, oesophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, appendix, colon, rectum); The accessory digestive organs include salivary glands, liver, pancreas, gallbladder
These organs aid in mechanical and chemical digestion.

The Endocrine System

The endocrine system uses chemical messengers called hormones. It regulates cellular and/or tissue function.
The endocrine glands include the pituitary gland (anterior and posterior lobes), thyroid gland, parathyroid glands, adrenal glands; pancreas, ovaries, testes, others.
These glands secrete hormones to regulate blood glucose levels; stress response; calcium balance & other essential functions.

The Immune System

The Immune system is composed of organs like thymus, spleen, lymph nodes and bone marrow. It is involved in both innate and adaptive immune responses, with both physical and cellular responses.

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Description

Test your knowledge on smooth muscle contraction, heart muscle physiology, and the roles of various hormones in metabolism and reproduction. This quiz covers essential concepts of muscle function, hormone secretion, and feedback mechanisms crucial for understanding human physiology.