Human Physiology BIO1220 Exam

Atom

Consists of protons and neutrons in the nucleus surrounded by electrons in shells.

Molecule

Most stable when the electron shell is complete; formed by sharing electrons between atoms.

Ions

Atoms with a positive or negative charge due to an unequal number of electrons and protons.

Free radicals

Atoms or molecules with unpaired electrons, highly reactive and potentially harmful.

Chemical bonds

Forces holding atoms in a molecule or compound, influenced by the number of electrons in the outer shell.

Exergonic

Spontaneous chemical reaction releasing free energy.

Endergonic

Nonspontaneous chemical reaction absorbing energy from the surroundings.

Organic compounds

Contain carbon, usually large molecules like carbohydrates, lipids, proteins, and nucleic acids.

Inorganic compounds

All others like water, salts, acids, and bases.

pH scale

Measures acidity or basicity of a solution; acidic (0-6), neutral (7), basic (8-14).

Buffers

Molecules that resist abrupt changes in pH, crucial for maintaining a constant pH in living cells.

Carbohydrates

Sugars and starches providing energy, including monosaccharides, disaccharides, and polysaccharides.

Lipids

Fats and oils containing carbon, hydrogen, and oxygen, used for energy storage and structural purposes.

Proteins

Basic structural material of the body, composed of amino acids, essential for various functions in the body.

Nucleic acids

Large molecules like DNA and RNA composed of nucleotides, crucial for genetic information and protein synthesis.

Cilia

Structures that propel fluids across cell surfaces, firmly attached in place, found in cells of the respiratory tract.

Flagella

Structures similar to cilia but generally move the entire cell, longer in length, found in sperm cells.

Cell to cell adhesion

Mechanism where plasma membranes participate in binding cells together, facilitated by three types of cell junctions:tight junctions, desmosomes, and gap junctions.

Tight junctions

Integral proteins in adjacent cells fuse together, creating selective barriers primarily found in epithelial tissues.

Desmosomes

Act like a zipper to hold cells together, important in tissues experiencing mechanical stress like muscle and skin, providing increased tensile strength.

Gap junctions

Structures used for communication between adjacent cells, allowing passage of small signaling molecules, especially abundant in cardiac and smooth muscle tissues.

Membrane transport

Process where substances pass between cells and the extracellular matrix, facilitated by the selectively permeable plasma membrane.

Diffusion

Movement of solutes down a concentration gradient, influenced by temperature and size of molecules, essential for processes like oxygen diffusion in the body.

Osmosis

Movement of water across a selectively permeable membrane, driven by differences in solute concentrations, crucial for maintaining cell shape and function.

Isotonic solution

Solution with the same solute concentration inside and outside the cell, leading to no net movement of water and maintaining cell shape.

Hypertonic solution

Solution with a higher solute concentration outside the cell, causing water to flow out and cells to shrink.

Hypotonic solution

Solution with a lower solute concentration outside the cell, leading to water influx and cell swelling or bursting.

Endocytosis

Process of moving substances into the cell through mechanisms like phagocytosis, pinocytosis, and receptor-mediated endocytosis.

Exocytosis

Process of moving substances out of the cell, often used for secreting large molecules like hormones and neurotransmitters.

Cytoplasm

Cellular component consisting of cytosol and organelles, responsible for various cellular functions like energy production and protein synthesis.

Nucleus

Control center of the cell, containing genetic material and providing instructions for protein synthesis, enclosed by a selectively permeable membrane with nuclear pores.

Cell to cell communication

Involves electrical and chemical signals, with local communication mechanisms like gap junctions, cell-to-cell contact, and paracrine/autocrine signals.

Long-distance communication

Involves electrical or chemical signals, where endocrine cells release hormones into the blood for distribution throughout the body, and the nervous system uses neurotransmitters for rapid effects.

Naloxone

A drug that acts as an opioid antagonist by blocking the opioid receptor, used to treat opioid overdose.

Hormone disruptors

Substances that can mimic or block particular hormones, leading to increased or decreased cellular responses.

BPA (Bisphenol A)

An example of a hormone disruptor that can bind to estrogen or androgen receptors, affecting metabolism, tumor growth, and male fertility.

Homeostatic reflex pathway

Cellular signaling systems responsible for maintaining homeostasis, involving 7 steps:stimulus, sensor, input signal, integrating centre, output signal, target, and response.

Neurons

Cells responsible for the reception, transmission, and processing of stimuli, categorized into multipolar, bipolar, and pseudounipolar types.

Glial cells

Supportive cells in the nervous system, including oligodendrocytes, Schwann cells, astrocytes, ependymal cells, and microglial cells.

Membrane potential

The electrical charge difference between the inside and outside of a cell, maintained by the sodium-potassium pump.

Action potentials

Brief changes in membrane potential that allow for the transmission of electrical signals along neurons, involving depolarization, repolarization, and the role of sodium and potassium ions.

Synapse

The junction between two neurons or a neuron and a muscle/gland cell, responsible for the transmission of nerve impulses through chemical neurotransmitters.

Neurotransmitters

Chemicals that relay signals between nerve cells, can be excitatory or inhibitory, influencing various functions like movement, mood, and cognition.

Medulla oblongata

The hindmost part of the brain responsible for controlling more routine functions like respiration and cardiovascular function.

Cervical enlargement

Located at the base of the neck, responsible for the control of the upper limb.

Lumbosacral enlargement

Found in the lower back, responsible for the control of the lower limb.

Grey matter

Contains dendrites, cell bodies of neurons, unmyelinated axons, and glial cells, forming the cortex covering most of the brain's surface.

White matter

Composed of myelinated axons, located deep to the grey matter in the brain and spinal cord.

Cauda equina

Nerve fibers below the end of the spinal cord, extending from the second lumbar vertebrae.

Ventricles and Cerebrospinal fluid

Brain's hollow cavities producing cerebrospinal fluid that circulates around the brain and spinal cord, cushioning them from injury.

Meninges

Three layers of connective tissue surrounding the brain and spinal cord, including the pia mater, arachnoid mater, and dura mater.

Corpus callosum

The largest tract connecting the left and right cerebral hemispheres, facilitating communication between them.

Limbic system

A ring of structures around the brainstem involved in regulating emotions, motivation, aggression, fear, sex, and memory.

Smooth Muscle Function

Involved in endocrine regulation, circulation, heart function, and digestion among other systems.

Denervation Hypersensitivity

Condition where damage increases sensitivity to stimulating agents in the absence of nerve stimulation.

Autonomic Nervous System (ANS)

Regulates intrinsic activity, affecting functions like heart rate; divided into sympathetic and parasympathetic divisions.

Sympathetic Division

Originates in thoracic and lumbar regions, with short preganglionic fibers and long postganglionic fibers.

Parasympathetic Division

Originates in cranial and sacral regions, with longer preganglionic fibers and short postganglionic fibers.

Neurotransmitters

Acetylcholine released by all preganglionic fibers and parasympathetic postganglionic fibers; noradrenaline released by most sympathetic postganglionic fibers.

Enteric Nervous System (ENS)

Controls GI tract movement, fluid exchange, and gastric secretion; part of the ANS with sensory and motor functions.

Sensory Receptors

Convert environmental stimuli into action potentials; categorized by energy type like chemoreceptors, mechanoreceptors, photoreceptors, and thermoreceptors.

Skin Receptors

Include free nerve endings for temperature, nociceptors for pain, and specialized receptors for touch, pressure, and proprioception.

Taste and Smell Chemoreceptors

Respond to chemicals in taste buds and olfactory receptors; involve different types of taste cells and olfactory sensory neurons.

Rods

Responsible for black-and-white vision under low light conditions.

Cones

Enable sharp color vision in brighter light conditions.

Retina

Comprises rods, cones, and other neuron layers; objects usually fall off fovea.

Rhodopsin

Purple pigment in rods that dissociates into components when stimulated by light.

Cones Types

Red, green, and blue cones containing photopsins absorbing different wavelengths.

Neural Pathways

Approximately 120 million rods, 6 million cones in each retina; 20:1 ratio.

Fovea

Area with highest visual acuity, containing only cones.

Lens

Focuses light on the retina, activating rods and/or cones.

Optic Nerve

Composed of ganglion cell axons, transmitting visual information to the brain.

Muscle Types

Skeletal (striated, multinucleate), Cardiac (striated, branched), Smooth (nonstriated, spindle-shaped).

Sarcomeres

Basic unit of muscle contraction, composed of actin and myosin filaments.

Muscle Contraction

Involves actin sliding over myosin, shortening the muscle.

Neuromuscular Junction

Site where motor neuron axon contacts muscle fiber, releasing acetylcholine.

Cross-Bridge Cycle

Process involving myosin and actin interaction during muscle contraction.

Motor Unit

Consists of one neuron and all muscle fibers it innervates, contracting together.

Isometric vs

Isometric maintains muscle length, isotonic shortens the muscle.

Muscle Twitch

All-or-none response to a single stimulus, involving latent period, contraction, and relaxation.

Muscle Fiber Types

Slow twitch (efficient, fatigue-resistant) and fast twitch (explosive, fatigable) fibers.

Glycolytic vs

Glycolytic fibers produce ATP less efficiently, while oxidative fibers are more efficient.

Cardiac Muscle

Striated muscle with branched cells, interconnected by gap junctions, and automatic electrical signals.

Smooth Muscle

Found in various organs, lacks sarcomeres, regulated by autonomic neurons, and contracts slowly.

Gap Junctions

Connections between cells that allow for direct communication and passage of ions and small molecules

Cardiac Physiology

Study of the function and activities of the heart, including its muscle cells and electrical conduction system

Pacemaker Cells

Specialized cells in the heart that generate electrical impulses to regulate the heart's rhythm

Conduction Fibers

Specialized muscle cells that conduct electrical impulses quickly in the heart

Electrocardiogram (ECG)

A recording of the electrical activity of the heart, showing the P wave, QRS complex, and T wave

Stroke Volume

The volume of blood pumped by each ventricle per heartbeat

Hemodynamics

The study of blood flow through the vessels, influenced by pressure, resistance, and vessel characteristics

Baroreceptors

Receptors that detect changes in blood pressure and help regulate it

Renin-Angiotensin-Aldosterone System

Hormonal system that regulates blood pressure and fluid balance

Leukocytes

White blood cells involved in immune responses and defense against infections

Monocytes

Make up 2-8% of all WBC, important phagocytes, tend to work outside blood vessels, develop into macrophages

Lymphocytes

Make up 20-40% of all WBC, 99% found in interstitial fluid, 3 major types:B-cells, T-cells, null cells, complex functions in immune system

Platelets

Fragments of megakaryocytes, lack nuclei but capable of movement, live for 5-9 days, important in blood clotting

Antigens

Molecules on cell surfaces, recognized as foreign, trigger immune responses, crucial in blood typing and transfusion reactions

Blood Typing

ABO system with antigens A and B, 4 blood types, importance of matching types between donors and recipients

Rh factor

Antigens on RBCs, Rh positive or negative, critical in pregnancies with Rh incompatibility