Comprehensive Human Physiology and Cell Biology Review for Unit 1 Test

Physiology

Physiology is the study of the normal functioning of the human body and its component parts, including chemical and physical processes.

Levels of organization

Atoms -> molecules-> cells->tissues->organs->organ system-> organism-> population of one species-> ecosystem of different species-> biosphere

Circulatory system function

Carries blood throughout the body and exchanges oxygen and CO2 in the systemic capillaries and carries the CO2 to the lungs to be discarded.

Respiratory system function

Exchanges oxygen and carbon dioxide between the internal and external environment.

Endocrine system function

Produces regulatory hormones that help with body processes and function.

Nervous system function

Processes all information and maintains body functions through chemical and electrical impulses.

Digestive system function

Mechanical and chemical digestion of food, as well as the absorption of nutrients and excretion of wastes.

Urinary system function

Maintenance of solutes and water in the body, as well as excretion of wastes.

Integumentary system function

Protection from the external environment.

Musculoskeletal system function

Movement, generation of heat, and support.

Reproductive system function

Perpetuation of the species.

Immune system function

Produces antibodies that help to destroy foreign invaders.

Four major themes of physiology

Energy, Information flow, Structure and function are closely related, Homeostasis.

Homeostasis

It is the maintenance of the internal environment, so it doesn't stray too far from the setpoint of the body.

Extracellular compartment

Composed of two different substances- interstitial fluid and plasma. The extracellular compartment is the fluid that surrounds the cells and serves as a buffer between the cells and the outside environment.

Intracellular compartment

This is the fluid found within the cell. The ICF is important because it houses organelles, which is essential for cellular processes.

Components of a control system

Input signal, Integration center, Output signal.

Four major groups of biomolecules

Proteins, carbohydrates, nucleotides, lipids.

High-energy electrons

These are electrons that can capture energy from their environment and transfer it to different atoms, allowing for important processes such as synthesis, movement, and other vital functions.

Radical electrons

These are very unstable molecules. Much is not known about them, but they are thought to be a part of the aging process and the development of certain diseases.

Covalent bonds

When two atoms have unpaired electrons, they can form a bond and share them.

Ions

When an atom loses or gains electrons, it gains a positive or negative charge. This is the basis of electrical signaling in the body.

Covalent bonds vs Noncovalent bonds

Covalent bonds are formed when two or more atoms share electrons. Ionic bonds form through the attraction of positive and negative charges.

Solubility and polarity of molecules

Like dissolves like. Polar solvents dissolve polar molecules and those with ionic bonds, but do not dissolve nonpolar molecules.

pH

The pH is the concentration of hydrogen ions within the body or a solution. The higher the hydrogen ion concentration, the lower the pH.

Equation of pH

The equation of pH is the -log[H].

Functions of proteins

Proteins in the body have several functions including catalyzing metabolic reactions, aiding cellular communication, exchanging molecules and ions, acting as signal molecules, transporting molecules, providing immunity, and regulating gene expression.

Specificity

The protein's ability to bind to only specific ligands.

Affinity

A protein's attraction to specific ligands; high affinity means more likely to bind, while low affinity means unlikely to bind.

Saturation

The condition in which all the receptor proteins' binding sites are occupied by a ligand, preventing increased activity despite increased substrate concentration.

Competition

When more than one substrate can bind to a protein, affecting binding and activity.

Allosteric competition

When a substrate binds to a protein outside the binding site, changing the conformation and preventing binding to its specific ligand.

Competitive inhibition

Occurs when two or more substrates can bind in a protein's active site, potentially hindering the binding of the activating substrate.

Ways to modify protein activity

Protein activity can be modified through allosteric competition, denaturation, and chemical modulators.

Chemical modulators

Molecules that can bind to a protein and alter its ability to function, either enhancing or completely rendering the protein inactive.

Modulator

A factor that influences either protein binding or protein activity.

Body compartments

There are 3 body compartments: cranial cavity (contains the brain), thoracic cavity (contains lungs and heart), and abdominopelvic cavity (contains abdomen and pelvis organs).

Functions of the cell membrane

The cell membrane separates ICF and ECF, regulates ion and molecule exchange, provides structural support, and facilitates communication between cells and their environment.

Mitochondria

Organelles responsible for cellular respiration and ATP production through oxidative phosphorylation; they have a double membrane and contain their own DNA.

Ribosomes

Small subunits that help to synthesize proteins.

Rough ER

Endoplasmic reticulum with ribosomes on its surface, aiding in protein synthesis.

Smooth ER

Endoplasmic reticulum without ribosomes, involved in detoxifying drugs and alcohol, storing calcium, and synthesizing fatty acids.

Lysosomes

Organelles that contain digestive enzymes to digest bacteria and other unwanted foreign molecules.

Peroxisomes

They degrade long-chain fatty acids and foreign toxic molecules. Filled with hydrogen peroxide.

Golgi Apparatus

modifies, packages, and ships out proteins in vesicles. They have folds called cisternae.

Extracellular Matrix

secreted by the cell, contains proteoglycans and insoluble protein fibers, helps with the structure and stability of cells, and allows communication with the external environment.

Proteoglycans

glycoproteins that are covalently bonded to polysaccharide chains.

Cell Adhesion Molecules

membrane proteins that help to anchor the cell to the ECM and to each other.

Gap Junctions

Connexin protein found in the membrane helps to create hollow 'tube-like' projections between cells, allowing for communication.

Tight Junctions

proteins claudin and occludin help to fuse the cells to restrict the movement of materials between cells.

Anchoring Junctions

type of junction that helps to attach cells to the ECM, done by cadherins in vertebrates.

Adherens Junctions

link actin fibers in adjacent cells together.

Desmosomes

type of cell-to-cell junction that uses cadherin proteins to attach cells to the intermediate filaments of the cytoskeleton.

Hemidesmosomes

attach epithelial cells to the extracellular matrix using integrin proteins.

Focal adhesion

tie intracellular actin fibers to different matrix proteins such as fibronectin.

Tissue Types

Nervous, Epithelial, Muscle, Connective tissue.

Epithelial Types

transport, exchange, ciliated, protective, and secretory.

Connective Tissue Types

loose, dense regular, dense irregular, adipose, blood, cartilage, and bone.

Muscle Types

smooth, skeletal, cardiac.

Neural Types

Neurons and Glial cells.

Cell Death

Necrosis of tissue is unregulated and can damage the tissue surrounding it.

Apoptosis

programmed cell death that allows tissues to get rid of damaged cells without disrupting the cells around it.

Stem Cells

Multipotent stem cells can differentiate into a variety of different cell types in that tissue, replacing damaged or dead cells.

Osmotic Equilibrium

when water will move through a cell's membrane until the water concentration inside and outside of the cell is equal.

Chemical Disequilibrium

occurs when the concentrations of solutes in the intracellular compartment and the extracellular compartments are not equal.

Osmolarity

the concentration of a solution expressed as the total number of solute particles per liter.

Tonicity

how a cell will react when put into a solution (shrink, swell, or remain the same).

Channel Proteins

water-filled passages between the ECF and ICF that allow small ions to flow down their concentration gradient into or out of the cell; a passive process.

Carrier Proteins

have a binding site within them; when an ion binds, it causes a conformational change and makes the protein turn to face the inside of the cell.

Conformational Change

A structural alteration in a protein that occurs when an ion binds to it, causing the protein to face the inside of the cell.

Aquaporins

Proteins that facilitate the passive movement of polar water molecules across the cell membrane.

Gated Channels

Channels that allow ions to pass through the membrane in response to specific stimuli.

Chemical-gated Channels

Channels that respond to chemical messages within the cell or ligands binding to the receptor.

Mechanical-gated Channels

Channels that respond to physical forces such as pressure or temperature changes.

Voltage-gated Channels

Channels that open or close when the electrical state of the cell changes.

Sodium-potassium ATPase

A pump that moves 3 Na+ ions from the ICF to the ECF using ATP, and 2 K+ ions from the ECF to the ICF.

Primary Active Transport

Transport that directly uses ATP to move molecules against their concentration gradient.

Sodium-Glucose Co-transport

A process where sodium binding creates a conformational change that allows glucose to enter the cell against its concentration gradient.

Secondary Active Transport

Transport that uses the potential energy from the movement of a molecule down its concentration gradient to push another molecule against its concentration gradient.

Endocytosis

An active transport process that brings larger molecules into the cell by forming a vesicle.

Receptor Mediated Endocytosis

A process where ligands bind to a receptor complex, which is then internalized to form a vesicle.

Phagocytosis

A process where a phagocyte engulfs a bacterium or foreign body, forming a phagosome.

Exocytosis

The process where an intracellular vesicle fuses with the cell membrane to transport a molecule out of the cell.

Transcytosis

A process where a molecule is brought into a cell via receptor-mediated endocytosis and then expelled on the opposite side by exocytosis.

Paracellular Transport

Transport through the junctions between adjacent cells.

Transcellular Transport

Transport through the actual cells themselves.

Resting Membrane Potential

The electrical gradient between the extracellular and intracellular components of the cell, representing potential energy due to charge differences.

Ionic Concentrations in ICF

Higher concentrations of phosphate and K+ ions.

Ionic Concentrations in ECF

Higher concentrations of Na+ and Cl- ions.

Ion permeability

The ability of the ions to go through the cell membrane.

Local communication

Communication that occurs between cells in close proximity, including gap junctions, contact-dependent signals, autocrine and paracrine signaling.

Long distance communication

Communication that takes place between distant parts of the body, involving the endocrine system (hormones) and nervous system (neurotransmitters and neurohormones).

Neurotransmitters

Chemicals secreted by a neuron that has to cross a small gap to reach its target.

Neurohormones

Chemicals released by a neuron into the blood for actions at distant targets.

Receptor binding sequence

The signal molecule will bind to a receptor, activating it, which then activates intracellular proteins that alter target proteins to elicit a response.

Receptor-Channel

A ligand binds to a receptor on the extracellular side, opening the channel for ions to flow in, generating an electrical signal that alters proteins to elicit a response.

Receptor-Enzymes

A ligand in the ECF binds to a receptor protein, activating an enzyme inside the cell, typically tyrosine kinase, which phosphorylates proteins and can amplify the signal.

GPCRs

G-protein coupled receptors that, upon ligand binding, activate G-proteins which then activate adenylyl cyclase or phospholipase C, leading to various cellular responses.

Adenylyl cyclase

An enzyme activated by GPCRs that converts ATP into cyclic AMP, which activates protein kinase A.

Phospholipase C

An enzyme activated by GPCRs that converts membrane phospholipids into DAG and IP3, leading to protein phosphorylation and calcium release.