Units 1-4 Learning Objectives Flashcards
Define the terms: anatomy and physiology and explain how anatomy and physiology
complement each other.
1) Anatomy: Examining the structure of the human body
2) Physiology: The study of function of the human body
3) Anatomy and physiology complement each other because of the unity of form and function
Describe gross anatomy and give 3 examples
Gross anatomy is a type of anatomy that studies structures that can be seen with the eyes. 3 examples of gross anatomy being applied in medicine are dissection, exploratory surgery, and medical imaging.
Name 3 areas of microscopic anatomy and describe them
3 areas of anatomy that study microscopic structures too small to see with your eye are histology, cytology, and ultrastructure.
Histology is the examination of tissues under a microscope.
Cytology is the study of structure and function of cells.
Ultrastructure is the study of viewing detail under an electron microscope.
Name 3 areas of physiology and describe them
3 subdisciplines of physiology are Neurophysiology (physiology of the nervous system) Endocrinology (physiology of hormones) and Pathophysiology (the study of the mechanisms of disease).
Describe the subdiscipline of comparative physiology and why it’s so important
Comparative physiology is another subdiscipline of physiology and is the study of another species to learn about body functions. Comparative physiology is important to physiology as a whole because physiology, unlike anatomy, requires live subjects due to the fact that you cannot observe function on a cadaver, so often relies on animals to perform research that will then become preliminary research for human medicine.
Describe some aspects of experimental design that help ensure objective and reliable
results.
Having a control group and an experimental group, replicating the experiment multiple times, and ensuring there’s no cross-contamination.
Give the levels of human structure from the most complex to the simplest (hierarchy of
complexity).
Organism, organ system, organ, tissue, cell, organelle, molecule, atom.
*Note: Organelles, molecules, and atoms are not considered to be alive; cells are the smallest unit of life
List the nine characteristics of life.
Organization, cellular composition, metabolism, responsiveness, movement, homeostasis, reproduction, development, and evolution of a population.
Define homeostasis
Maintaining relatively stable internal conditions [regardless of external conditions].
Define a gradient and give examples of gradients in the human body.
A gradient is defined as a difference in chemical concentration, charge, temperature, or pressure between two points.
Examples:
1) blood flowing from a place of higher pressure (near the heart) to a place of lower pressure, sodium-potassium gradients
2) heat flowing from an area of high heat (inside the body) to an area of low heat (outside the body)
3) dietary glucose flowing from an area of high concentration to low concentration (into intestinal cells).
Describe which direction do gradients flow naturally and what would be necessary if you
went “against” or “up” a gradient.
Molecules naturally flow down gradients (from areas of high concentration to low concentration). If you went against the gradient (from an area of low concentration to high), that would require a cell to use energy (ATP).
Define the terms: element, atom, molecule, and compound.
Element: The simplest form of matter with unique properties.
Atom: building blocks for each element.
Molecule: chemical particle composed of two or more atoms united by a chemical bond.
Compound: molecule composed of two or more different elements.
List the six elements that comprise 98.5% of our body weight.
Oxygen (O), Carbon (C ), Hydrogen (H), Nitrogen (N), Calcium (Ca), and Phosphorus (P).
Describe the three particles that make up an atom and their arrangement in an atom.
Neutrons have no charge, and they determine atomic mass (number of protons + number of neutrons = atomic mass). Atoms of an element with a different number of neutrons than protons are called isotopes.
Protons have a positive charge, and they determine the identity of an element as well as its atomic number (atomic number = number of protons the atom has).
Electrons have a negative charge. Atoms of an element with a different number of electrons than protons are called ions (or electrolyte), and they have a positive (cation) or negative charge (anion) (more electrons = more negative).
Neutrons and protons are found in the nucleus of an atom, whereas electrons are found in shells (or energy levels) around the nucleus. The first energy level is full with 2 electrons, and the second and third levels are full with 8 electrons. Electrons in the outermost level are called valence electrons.
Define the terms isotope and radioactive isotope.
Isotope: when an atom has a different number of neutrons than protons.
Radioactive isotope: an isotope that disintegrates over time and gives off energy.
Describe ways we can use radioactive isotopes in medicine
They can be used for radiation therapy and diagnostic procedures. This includes PET scans, using I-131 determine size and activity of the thyroid gland, Hida scans (Tc-99 technetium with a ½ life of 6 hours), Cobalt-60 for cancer.
Other examples of radioactive isotopes include UV radiation, X-rays, alpha particles, beta particles, gamma rays.
Discuss how cations and anions are formed.
If an atom gains an electron, then it becomes an anion (negatively charged). If an atom loses an electron, then it becomes a cation (positively charged). This only happens to atoms without a full outer shell (i.e. atoms that are not noble gas elements).
List each type of chemical bond in order of relative strength from strongest to weakest.
Covalent bonds, ionic bonds, hydrogen bonds.
Discuss the “octet rule” and how we apply it to predict which type of chemical bond will
be formed.
The octet rule is the concept that atoms gain or lose electrons to have full outer shell. We use this rule to help figure out if two atoms are going to share electrons and form a covalent bond, or if one atom will donate an electron to the other atom and form an ionic bond. For example we can determine if two atoms are eligible to become a cation and an anion (i.e. if one atom only has one electron in an outer shell) and by using the octet rule, we know that the atom wants to get rid of that electron, so if it gets near an atom with one missing electron, it will donate that electron to the atom with the missing electron, and the one the electron was donated to becomes an anion and the one that did the donating becomes a cation (and now both atoms have full outer shells), and now those two atoms have formed an ionic bond.
Explain the mechanism of ionic bonds, non-polar covalent bonds, polar covalent bonds,
and hydrogen bonds.
Ionic bonds: The donation of an electron from one atom to another; a bond between a cation and an anion.
Non-polar covalent bonds: Two or more atoms share electrons equally.
Polar covalent bonds: Two or more atoms share electrons unequally.
Hydrogen bonds: A weak charge attraction between a slightly positive hydrogen and a slightly negative oxygen (or nitrogen).
List a biological example of each type of bond
Hydrogen bonding: The bases in DNA form hydrogen bonds (ex: there’s two hydrogen bonds between A and T and three hydrogen bonds between C and G).
Ionic bonding: Ionic bonds help shape tertiary and quaternary structures of proteins, and NaCl is found in the human body and has an ionic bond.
Covalent bonding: Water molecules found in the human body are formed with covalent bonds, peptide bonds formed between amino acids, covalent bonds within each linear strand of DNA.
Define the terms mixture, solution, solute, solvent, colloid, and suspension.
Mixture: physically blended but not chemically combined (ex: body fluids are mixtures of chemicals).
Solution: A homogenous mixture of two or more substances (a solute and solvent) in relative amounts that can be varied continuously up to the limit of solubility.
Solute: the substance that dissolves in a solvent to produce a homogeneous mixture.
Solvent: the substance in which a solute dissolves to produce a homogeneous mixture.
Colloid: a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance.
Suspension: a heterogeneous mixture of a fluid that contains solid particles sufficiently large for sedimentation.
Describe the five biologically important properties of water.
– Solvency: ability to dissolve other chemicals; water is referred to as the ‘universal solvent’.
– Cohesion: water molecules cling to each other; water is very cohesive due to its hydrogen bonds. This in turn causes surface tension.
– Adhesion: water adheres to other substances (ex: water adheres to large membranes reducing friction around organs).
– Chemical reactivity: ability to participate in chemical reactions; water ionizes into and ionizes many other chemicals (acids and salts).
– Thermal stability:Water has high heat capacity (absorbs and releases large amounts of heat before changing temperature); this is because hydrogen bonds inhibit temperature increases by
inhibiting molecular motion. This property is what helps keep the internal temperature of our bodies stable.
Describe which types of molecules will easily mix with water and which will not.
Molecules with polar covalent bonds will easily mix with water, but molecules with nonpolar covalent bonds will not.
Define the terms pH, acid, base, and buffer.
pH: A measure of hydrogen ion concentration.
Acid: A chemical species that donates protons or hydrogen ions and/or accepts electrons. Has a low pH.
Base: A chemical species that donates electrons, accepts protons, or releases hydroxide (OH-) ions in aqueous solution. Has a high pH.
Buffer: A solution that can resist pH change upon the addition of an acid or a base by neutralizing small amounts of that acid or base.
Define energy and work.
Energy: The capacity to do work [move something].
Work: To move something.
Differentiate between potential energy and kinetic energy.
Potential energy is energy stored in an object, but not currently doing work, whereas kinetic energy is the energy of motion and doing work.
Differentiate between decomposition reactions and synthesis reactions and be able to
give examples of each
Decomposition reactions are where a large molecule breaks down into two or more smaller ones (ex: AB > A + B), whereas synthesis reactions are where two or more small molecules combine to form a larger one (A + B > AB).
List the three factors that will increase reaction rates.
Reaction rates increase when the reactants are more concentrated, the temperature rises, and when a catalyst is present.
Define metabolism and its two subdivisions.
Metabolism: all chemical reactions of the body.
Catabolism: energy-releasing decomposition reactions that break covalent bonds and produce smaller molecules.
Anabolism: energy-storing synthesis reactions that require energy input (ex the production of protein or fat)
Side note: Anabolism is driven by energy released by catabolism.
Define the term organic molecule.
compounds containing carbon.
Explain the relationship between macromolecules, monomers, and polymers.
Macromolecules are made up of polymers, and polymers are made up of monomers.
Describe hydrolysis and dehydration synthesis.
Hydrolysis is splitting a polymer by the addition of water. Dehydration synthesis is when monomers covalently bind together to form a polymer with the removal of a water molecule
Identify the monomers and polymers of carbohydrates and their functions.
Monomers: Monosaccharides: Glucose, galactose, and fructose are examples, and they are simple sugars that are produced by the digestion of complex carbohydrates. Glucose functions as blood sugar in the body.
Disaccharides: Sucrose (table sugar) = Glucose + fructose, Lactose (sugar in milk) = Glucose + galactose, Maltose (grain products) = Glucose + glucose.
Polysaccharides: Ex: Glycogen is a glucose polymer that is stored in the liver and skeletal muscles.
Describe how all lipids are related.
In all lipids, either part of or the entire molecule is hydrophobic.
Describe the structure and functions of triglycerides (neutral fats) and phospholipids.
Triglycerides are three fatty acids linked to glycerol, and their primary function is energy storage (contain 2x more energy than carbs or proteins), and they also help with insulation and padding (shock absorption (adipose tissue)).
Phospholipids are similar to neutral fats except one fatty acid is replaced by a phosphate group; consists of two hydrophobic fatty acid tails and a hydrophilic phosphate head. They make up the phospholipid bilayer of the cell membrane.
Describe how triglycerides are transported in the human body.
Because triglycerides are hydrophobic, they are packaged within intestinal cells along with cholesterol molecules in phospholipid vesicles called chylomicrons, which allows them to move within the aqueous environment of the lymphatic and circulatory systems.
Describe what “parent” steroid from which the other steroids are synthesized.
Cholesterol, which is important for nervous system function and structural integrity of all cell membranes; 15% of our cholesterol comes from our diet.
Describe the structure of an amino acid
Amino acids have a central carbon with three attachments (Amino group (NH2), carboxyl group (—COOH), and radical group (R group)). Amino acids only differ in the R group.
Describe the formation of peptide bonds
Peptide bonds are bonds between two amino acids that joins their carboxyl groups together, and they’re formed by dehydration synthesis; the resulting chain is called a peptide.
Explain the four levels of organization of protein structure and how these contribute to
so many different proteins.
Primary: Sequence of amino acids joined by peptide bonds.
Secondary: Alpha helix or beta sheet formed by hydrogen bonding
Tertiary: Folding and coiling due to interactions among R groups and between R groups and surrounding water. This is what makes proteins really unique.
Quaternary: Association of two or more polypeptide chains with each other.
These structures create what is called a conformation, which is the unique, three-dimensional shape of protein, which is crucial to function. So many proteins exist because there are many different ways proteins can fold in each level of organization of protein structure.
Differentiate between a fibrous protein and a globular protein.
Fibrous proteins are generally composed of long and narrow strands and have a structural role (they are something). Examples include keratin and collagen.
Globular proteins generally have a more compact and rounded shape and have functional roles (they do something). Examples include carriers, catalysis, motor proteins, etc.
Discuss the two major ways to denature a protein, and define denaturation.
Extreme heat or pH can denature proteins. Denaturation is an extreme conformational change that destroys a protein’s ability to function.
Describe some functions of proteins in the human body
Structure (ex: keratin and collagen)
Communication (ex: some hormones and receptors)
Membrane transport (ex: channel proteins in cell membranes govern what passes)
Carriers (ex: carrier proteins transport solutes to the other side of membranes)
Catalysis (ex: most enzymes are globular proteins)
Recognition and protection (ex: antibodies are proteins)
Movement (ex: motor proteins, which are molecules with the ability to change shape repeatedly)
Cell adhesion (ex: proteins bind cells together and keeps tissues from falling apart. ex: sperm to egg).
Define an enzyme and describe the characteristics of enzymes.
Enzyme: proteins that function as biological catalysts and allow reactions to occur rapidly at body temperature; they do this by lowering the activation energy. They’re named for the substrate it acts upon plus the suffix -ase. They’re reusable because enzymes are not consumed by the reactions and they work at an astonishing speed (one enzyme molecule can consume millions of substrate molecules per minute). However, temperature, pH and other factors can change enzyme shape and function, which can alter the ability of the enzyme to bind to the substrate
Describe the three nucleic acids in the human body and their basic function.
DNA: contain millions of nucleotides and constitutes genes.
RNA: follows DNA instructions to assemble proteins
ATP: the body’s energy currency.
Describe the composition of nucleotides.
They contain a nitrogenous base (Adenine, Guanine, Cytosine, Thymine or Uracil), a sugar (ribose or deoxyribose), and one or more phosphate groups.
The components of cell theory are:
–All organisms composed of cells and cell products; organisms that don’t contain cells do not exist.
–The cell is the simplest structural and functional unit of life; anything simpler than a cell is not considered to be alive.
–An organism’s structure and functions are due to the activities of cells.
–Cells come only from preexisting cells, they don’t just spontaneously appear
–Cells of all species exhibit biochemical similarities
List the three components of a cell that can be viewed with a light microscope.
You can see the nucleus, where the plasma membrane is, and the cytoplasm.
Define extracellular fluid, intracellular fluid, interstitial fluid.
Extracellular fluid: Fluid within the body outside of the cells.
Intracellular fluid: Fluid contained within cells.
Interstitial fluid: Fluid between cells and tissues; one of the two major extracellular fluids in the body (the other one is plasma).
Differentiate between cytoplasm and cytosol.
Cytoplasm contains the organelles; cytosol does not. Cytosol is the word used to describe only the aqueous components of the cytoplasm.
Describe the structure of the plasma membrane.
The plasma membrane is the border of the cell, and it is arranged in a bilayer of phospholipids, with the hydrophobic tails of the phospholipids facing the interior of the plasma membrane. It also can contain integral proteins, and integral transmembrane proteins like protein channels, as well as cholesterol, peripheral proteins, and carbohydrate chains (carbohydrate chains are attached to the exterior side). There is a fuzzy exterior to the plasma membrane called the glycocalyx as well, and it provides the cell with protection, immunity to infection, and defense against cancer.
Explain the functions of the lipid, protein, and carbohydrate components of the plasma membrane.
The lipid component makes up the phospholipid bilayer of the plasma membrane, which constitutes 75% of the plasma membrane.
Proteins are 2% of the molecules within the plasma membrane, but make up 50% of the membrane’s weight. Proteins can act in the plasma membrane as receptors, enzymes, channels, carriers, cell-identity markers, and cell-adhesion molecules.
The carbohydrate chains help with cell recognition and adhesion, and they allow for cell-cell signaling and help in cell-pathogen interactions.
List what types of molecules pass through the phospholipid bilayer and which types
must use a protein channel or carrier.
Types of molecules that can pass through: Non-polar molecules, hydrophobic molecules, small molecules,
Types that need to use a protein channel or carrier: Polar molecules, hydrophilic molecules, large molecules, and ions/ charged molecules.
Discuss how the fluid mosaic model describes the plasma membrane.
The plasma membrane is incredibly flexible and if poked, the phospholipids will move vertically, but they will always reorient themselves into a bilayer because of the hydrophilic head and hydrophobic tails.
Differentiate between integral proteins and peripheral proteins.
Integral proteins: penetrate the plasma membrane.
Peripheral proteins: lie on the surface of the plasma membrane.
Describe the types and functions of gated channels
Ligand-gated channels are needed to respond to chemical messengers (like neurotransmitters) by opening or closing, voltage-gated channels are needed to respond to electrical signals (like electrical nerve impulses) by opening or closing, and mechanically-gated channels are needed to respond to physical stress on the cell by opening or closing (they are also an example of a stretch receptor). Channel proteins within the plasma membrane in general govern what goes into and out of a cell (excluding things that can pass straight through the plasma membrane).
What do carrier proteins do?
Carrier proteins transport solutes to other side of membrane
Describe the structure and functions of microvilli
Microvilli are extensions of the membrane (1–2 μm) that give the membrane 15 to 40 times more surface area, which helps in absorption. Thus, they’re best developed in cells specialized in absorption. They can be very dense and appear as a fringe; known as “brush border”.
Describe the structure and functions of cilia
Cilia are hair-like processes that are 7–10 μm long. Motile cilia are found in the respiratory tract, uterine tubes, ventricles of brain, and ducts of testes; they beat in waves sweeping material across a surface in one direction.
Describe the structure and functions of flagella
Flagella have a whip-like structure and are much longer than cilium. The tail of a sperm is the only functional flagellum in humans. Their movement is undulating, snake-like, corkscrew, with no power stroke and recovery strokes.
Describe the structure and functions of pseudopods
Pseudopods are continually changing extensions of the cell that vary in shape and size, and can be used for cellular locomotion and capturing foreign particles.
Define simple diffusion and give an example
Simple diffusion is defined as the net movement of particles from place of high concentration to place of lower concentration; it happens because of constant, spontaneous molecular motion; molecules collide and bounce off each other. It does not require energy or a membrane, and only non-polar hydrophobic molecules can enter cells using this method. Ex: oxygen permeating the cell membranes of lung cells.
Define osmosis and give an example
Osmosis is similar to simple diffusion, but it requires a selectively permeable membrane to be present. It’s defined as the diffusion of water through a selectively permeable membrane from an area of high concentration to an area of low concentration. It does not require energy, and does not use a carrier protein like facilitated diffusion. Ex: water moving into my interstitial cells after I drink water.
Define facilitated diffusion and give an example
Facilitated diffusion, like simple diffusion, is the net movement of something from areas of high concentration to low concentration. However, it moves a solute from a place of high concentration to a place of lower concentration using a carrier protein. It does not require energy. This is usually used to allow hydrophilic polar molecules to enter cells. Ex: the movement of glucose from the bloodstream and into cells, the diffusion of water into cells through aquaporins.
Define filtration and give examples
Filtration is where particles are driven through a membrane by physical pressure. Examples of this would be the filtration of water and small solutes through gaps in capillary walls, the delivery of water and nutrients to tissues, and the removal of waste from capillaries in the kidneys. It does not require energy from the cell either, like simple diffusion, osmosis, and facilitated diffusion.
Define primary active transport and give examples
Primary active transport is when a carrier protein moves the solute through a membrane up (against) its concentration gradient. Because it is moving against the concentration gradient (unlike simple diffusion, osmosis, facilitated diffusion, and filtration), this process requires energy. Examples would be the calcium pump (uniport) and the sodium–potassium pump (antiport).
Define vesicular transport and give examples
Vesicular transport is the movement of large particles, fluid droplets, or numerous molecules at once through the membrane in vesicles (bubble-like enclosures of membrane). Like primary active transport, it requires energy. Examples of this include phagocytosis (cells eating things), exocytosis (cells removing things), and pinocytosis (cells drinking things).
Describe the factors that influence the rate of diffusion.
1) Temperature: ^ temp = ^ motion of particles = ^ rate
2) Molecular weight: larger molecules move slower
3) Steepness of concentrated gradient: ^ difference = ^ rate
4) Membrane surface area: ^ area = ^ rate
5) Membrane permeability: ^ permeability = ^ rate
Define osmolarity and tonicity.
Osmolarity: The measure of total concentration of solute particles.
Tonicity: The concentration of non-permeating solutes.
Discuss the two conditions necessary for osmosis
Osmosis requires the presence of a concentration gradient, as well as the presence of a selectively permeable membrane.
Determine which type of solution (hypertonic, isotonic, or hypotonic) will cause crenation or cytolysis/hemolysis.
Hypertonic solutions cause crenation (cells shriveling from water leaving the cell), hypotonic solutions cause cytolysis/hemolysis (cells exploding from water entering the cell), and isotonic solutions do not do anything to cells since there is no concentration gradient.
Compare and contrast osmosis using simple diffusion versus facilitated diffusion (aquaporins).
Osmosis is very slow, like a dripping faucet, when using only simple diffusion. However, osmosis through facilitated diffusion allows water to pour into or out of a cell quickly. The more aquaporins a cell has, the faster water moves in and out of the cell.
Explain the difference between uniports, symports, and antiports and give examples of each.
Uniports moves molecules across the membrane independent of other molecules,
Antiports move two types of molecules across the membrane in opposite directions, and
Symports move two different molecules in the same direction.
Examples: calcium pump (uniport), the sodium–potassium pump (antiport), and moving glucose up its concentration gradient by using the energy from the movement of sodium ions that are moving down their gradient (symport).
Distinguish between phagocytosis, pinocytosis, and receptor-mediated endocytosis.
Phagocytosis: Cells eating things/ engulfing large particles; a type of endocytosis.
Pinocytosis: Cells drinking things; a type of endocytosis.
Receptor-mediated endocytosis: A more selective type of endocytosis that enables cells to take in specific molecules that bind to extracellular receptors.
Discuss the three types of protein fibers used for the cytoskeleton and the functions of each type.
Intermediate filaments are thicker and stiffer than microfilaments and participate in cell-to-cell adhesion; they give the cell its shape.
Microfilaments are about 6 nm thick and are made of the protein actin. They are widespread throughout the cell but especially concentrated in a fibrous mat called the terminal web (membrane skeleton) on the exterior side of the plasma membrane, and they provide support to the cell.
Microtubules (25 nm in diameter) are cylinders made of 13 parallel strands called protofilaments. Each protofilament is a long chain of globular proteins called tubulin. Microtubules radiate from an area of the cell called the centrosome. They hold organelles in place, form bundles that maintain cell shape and rigidity, and act somewhat like monorail tracks.
Discuss the structure and functions of peroxisomes
Detoxify certain harmful chemicals, enclose reactions that make toxic byproducts. Abundant in the cells found in the liver and kidneys.
Discuss the structure and functions of lysosomes
A package of enzymes bound by a membrane, they aid in intracellular hydrolytic digestion, phagocytosis, and autolysis.
Discuss the structure and functions of centrioles
They form the mitotic spindle during cell division, unpaired centrioles form basic structure of cilia and flagella.
Discuss the structure and functions of mitochondria
A kidney-bean shaped organelle specialized for synthesizing ATP.
Discuss the structure and functions of the golgi complex
It receives newly synthesized proteins from
rough ER, then sorts proteins, modifies proteins, and packages them into vesicles. Some vesicles become lysosomes, some vesicles migrate to plasma membrane and fuse to it, and some become secretory vesicles that store a protein product for later release.
Discuss the structure and functions of ribosomes
They’re small granules of protein and RNA that “read” coded genetic messages (messenger RNA) and assemble amino acids into proteins specified by the code.
Discuss the structure and functions of the smooth ER
A system of channels enclosed by a membrane, it synthesizes steroids and other lipids, detoxifies alcohol and other drugs, and stores calcium.
Discuss the structure and functions of the rough ER
It is composed of parallel, flattened sacs covered with ribosomes, and it synthesizes proteins and packages proteins for transport.
Discuss the structure and functions of the nucleus
Also known as the “brain of the cell”, it’s the largest organelle and it controls all cellular activity. It is enclosed in a the nuclear membrane, which is double membrane with pores surrounding the nucleus. Contains chromatin and chromosomes.
Discuss the structure and functions of the cytosol
The aqueous component of the cytoplasm of a cell; also called intracellular fluid/ ICF.
Discuss the structure and functions of the plasma membrane
Made up of phospholipids, proteins, and carbohydrate tails. Defines cell boundaries, governs interactions with other cells, and controls passage of materials in and out of the cell.
Discuss the structure and functions of the cytoplasm
Contains the organelles, cytoskeleton, inclusions (stored or foreign particles), and cytosol (intracellular fluid, ICF)
Define autolysis, autophagy, and phagocytosis
Phagocytosis: Cells eating things/ engulfing large particles; a type of endocytosis.
Autolysis: The destruction of cells or tissues by their own enzymes.
Autophagy: The digestion and disposal of surplus or nonvital organelles and other cell components in order to recycle their nutrients to more important cell needs.
Describe how lysosomes relate to the processes of autolysis, autophagy, and phagocytosis
Lysosomes help aid in phagocytosis (the cell eating things); after a neutrosome captures a bacteria in a phagosome, a lysosome merges with the phagosome, converting it to a phagolysosome, and contributes enzymes that destroy the invader. They also help aid in autolysis by releasing enzymes that will kill the cell. Lysosomes also digest and dispose of surplus or nonvital organelles and other cell components in order to recycle their nutrients to more important cell needs, which is autophagy.
Compare and contrast nuclear DNA and mitochondrial DNA.
Mitochondrial DNA (mtDNA) is a small, circular molecule that is more visually similar to the circular DNA of bacteria, not the linear DNA found in the cell nucleus. mtDNA also replicates independently from nuclear DNA. Mitochondrial DNA consists of 16,569 base pairs, comprising 37 genes, which is quite small when compared to the over 3 billion base pairs and about 20,000 genes in nuclear DNA. Both DNA and mtDNA are heritable, but you only inherit mtDNA from your mother, whereas you inherit your nuclear DNA from both of your parents.
Describe the structure of DNA.
DNA has a double helix structure and it’s made up of nitrogenous bases united by
hydrogen bonds. A purine on one strand is always bound to a pyrimidine on the other;
also, A–T have two hydrogen bonds, whereas C–G have three hydrogen bonds.
The law of complementary base pairing states that one strand determines the base
sequence of the other.
Explain how DNA and histone proteins are organized to form the chromosomes.
The DNA first winds around spools of proteins called histones to form the little granules (core particles), then the chromatin then folds into successive zigzags, loops, and coils, getting thicker and shorter as it does so. Then the DNA, which is 2 nm in diameter, is consolidated into chromatin strands 150 times thicker and 1,000 times shorter than the naked DNA. Finally, each chromosome is packed into its own spheroidal region of the nucleus, called a chromosome territory
Discuss the three specific parts of a DNA nucleotide.
Each DNA nucleotide contains a sugar (deoxyribose), a phosphate group, and one nitrogenous base (A, T, C, or G).
List the purine nitrogenous bases and the pyrimidine nitrogenous bases and describe
which purine base will make hydrogen bonds with which pyrimidine base.
Purines: Adenine & Guanine
Pyrimidines: Thymine & Cytosine
The purine adenine forms two hydrogen bonds with the pyrimidine thymine, and the purine guanine forms three hydrogen bonds with the pyrimidine cytosine.
Define the terms chromatin, chromosomes, and sister chromatids.
Chromatin: fine filamentous DNA material complexed with proteins.
Chromosomes: A complex of DNA and protein carrying the genetic material of a cell’s nucleus; consists of two sister chromatids. Normally there are 46 chromosomes in the nucleus of each cell except germ cells.
Sister chromatids: Two parallel filaments of identical DNA
Discuss the fours differences between DNA and RNA.
RNA differs from DNA in that it’s single stranded (it consists of just one nucleotide chain and not a double helix like DNA), ribose replaces deoxyribose as the sugar, uracil replaces thymine as a nitrogenous base, and it functions mainly in cytoplasm.
State the current definition of a gene
An information-containing segment of DNA that codes for synthesizing one or more proteins.
Describe how DNA codes for protein structure.
DNA triplets relate to the mRNA codons and those, in turn, relate to the amino acids of a protein; in other words, the nucleotide sequence in the DNA determines the amino acid sequence of a protein.
Describe the assembly of amino acids into a protein.
1) DNA double helix exists.
2) There are seven base triplets on the template strand of DNA
3) The corresponding codons of mRNA are transcribed from the DNA triplets
4) The anticodons of tRNA then bind to the mRNA codons
5) The amino acids are carried by those six tRNA molecules
6) The amino acids are linked into a peptide chain through peptide bonds; this is the primary structure of a protein.
7) Secondary structure formation: Alpha helix or beta sheet formed by hydrogen bonding
8) Tertiary structure formation: Folding and coiling due to interactions among R groups and between R groups and surrounding water. This is what makes proteins really unique.
9) Quaternary structure formation: Association of two or more polypeptide chains with each other.
Discuss the roles of messenger RNA, ribosomal RNA, and transfer RNA.
mRNA: carries code from nucleus to cytoplasm during translation.
tRNA: after the mRNA brings the code to the cytoplasm during translation, tRNA then delivers a single amino acid to the ribosome for it to be added to growing protein chain
rRNA: ribosomes are largely made up of rRNA and enzymes; after tRNA delivers the amino acid to the ribosome, the ribosome adds the amino acid to the protein chain.
The essential function of the three principal RNAs is to interpret the code in DNA and use those instructions to synthesize proteins
Describe where triplets, codons, and anticodons are found and be able to correctly give
the codon and anticodon if given a triplet code.
Seven base triplets are found in the template strand of DNA, and corresponding codons are found in the mRNA. Anticodons are found in tRNA.
Explain the process of transcription
In the nucleus, RNA polymerase reads bases from one strand of DNA, and then makes corresponding mRNA.
Describe the process of translation
1) Initiation Initiator tRNA (bearing methionine) pairs with start codon. Ribosome pulls mRNA molecule through it like a ribbon. When start codon (AUG) is reached, protein synthesis begins 2) Elongation Next, tRNA (with its amino acid) binds to the ribosome while its anticodon pairs with the next codon of mRNA. A peptide bond forms between methionine and the second amino acid. The ribosome slides to read the next codon. Next, tRNA with the appropriate anticodon brings its amino acid to the ribosome. Another peptide bond forms (between the 2nd and 3rd amino acids). Process continually repeats, extending the peptide into a protein 3) Termination Ribosome reaches stop codon, finished protein breaks away from ribosome, ribosome dissociates into two subunit
Explain what happens to a protein after its amino acid sequence has been synthesized.
1) Protein is formed by ribosomes on rough ER.
2) Protein is packaged into transport vesicle, which buds from ER.
3) Transport vesicles fuse into clusters that unload the protein into the Golgi complex.
4) The golgi complex modifies the protein structure.
5) The golgi vesicle containing the finished protein is formed.
6) Lastly, secretory vesicles release the protein by exocytosis.
Describe the process of DNA replication.
DNA unwinds from histones
An enzyme unzips a segment of the double helix exposing its nitrogenous bases
DNA polymerase builds new DNA strands
Newly made DNA wraps around histones
Discuss the three phases of interphase and what occurs in each phase.
1) G1: first gap phase
The interval between cell birth (from division) and DNA replication. The cell carries out normal tasks and accumulates materials for next phase
2) S: synthesis phase
The cell replicates all nuclear DNA and duplicates centrioles
3) G2: second gap phase
The second gap phase; the interval between DNA replication and cell division. The cell repairs DNA replication errors, grows and synthesizes enzymes that control cell division
Distinguish between the process of mitosis and cytokinesis.
Mitosis does not include the cell membrane splitting into two.
Describe the four phases of mitosis and explain what occurs in each of the phases.
1) Prophase
Genetic material condenses into compact chromosomes
46 chromosomes are made of two sister chromatids
Nuclear envelope disintegrates
Centrioles sprout spindle fibers (long microtubules)
Spindle fibers push centriole pairs apart
Some spindle fibers attach to kinetochores of centromeres of chromosomes
2) Metaphase
Chromosomes are aligned on cell equator
Shorter microtubules from centrioles complete an aster which anchors itself to inside of cell membrane
3) Anaphase
Enzyme cleaves two sister chromatids apart at centromere
Single-stranded daughter chromosomes migrate to each pole of the cell as motor proteins in kinetochores crawl along spindle fibers
4) Telophase
Chromosomes cluster on each side of the cell
Rough ER makes new nuclear envelope around each cluster
Chromosomes uncoil to chromatin
Mitotic spindle disintegrates
Each nucleus forms nucleoli
Describe the prophase phase of mitosis
Genetic material condenses into compact chromosomes
46 chromosomes are made of two sister chromatids
Nuclear envelope disintegrates
Centrioles sprout spindle fibers (long microtubules)
Spindle fibers push centriole pairs apart
Some spindle fibers attach to kinetochores of centromeres of chromosomes
Describe the metaphase phase of mitosis
Chromosomes are aligned on cell equator
Shorter microtubules from centrioles complete an aster which anchors itself to inside of cell membrane
Describe the anaphase phase of mitosis
Enzyme cleaves two sister chromatids apart at centromere
Single-stranded daughter chromosomes migrate to each pole of the cell as motor proteins in kinetochores crawl along spindle fibers
Describe the telophase phase of mitosis
Chromosomes cluster on each side of the cell
Rough ER makes new nuclear envelope around each cluster
Chromosomes uncoil to chromatin
Mitotic spindle disintegrates
Each nucleus forms nucleoli
List the 4 stages of mitosis in order
Prophase, metaphase, anaphase, telophase (PMAT)
Discuss factors that would inhibit cell division
- They snugly contact neighboring cells
- Nutrients or growth factors are withdrawn
- They undergo contact inhibition—the cessation of cell division in response to contact with other cells
Discuss factors that would promote cell division
- They have enough cytoplasm for two daughter cells
- They have replicated their DNA
- They have adequate supply of nutrients
- They are stimulated by growth factors (chemical signals)
- Neighboring cells die, opening up space
Name the four primary classes into which all adult tissues are classified.
Epithelial tissue, connective tissue, nervous tissue, and muscular tissue
Define histology
The study of tissues
Compare the general features of the four major tissue types.
All 4 tissues types are similar to each other in the following ways:
All tissue types are made up of cells.
All tissue types have an extracellular matrix
All cells and tissues occupy space
Contrast the general features of the four major tissue types.
The 4 tissue types vary in:
The types and functions of their cells
The characteristics of their matrix (extracellular material)
The relative amount of space occupied by their cells versus their matrix
Describe the unique functions of the epithelium
- It covers body surfaces and lines body cavities
- It protects deeper tissues from injury and infection
- It produces and releases chemical secretions; also involved with excretion and absorption
- It selectively filters substances
- It makes up most glands
Describe the unique characteristics of epithelium
- Its cells are very close together
- Its cells have a high rate of mitosis (regenerative)
- Has apical and basal surfaces
Name and describe the 4 types of simple epithelium
1) Simple squamous
Permits rapid diffusion or transport of substances
It secretes serous fluid
Found in: air sacs of lungs (alveoli), inner lining of blood vessels & heart (endothelium), and serosa
2) Simple cuboidal
It’s good at absorption and secretion, mucus production, and movement
Found in: Kidney tubules and certain glands (thyroid, mammary and salivary glands)
3) Simple columnar
Specializes in absorption and secretion; secretion of mucus
Has a brush border of microvilli, ciliated in some organs, and may possess goblet cells. It’s the only tissue with microvilli.
Made up of a single row of tall, narrow cells; oval nuclei in basal half of cell
Found in: the lining of the GI tract, the uterus, and uterine tubes
4) Pseudostratified columnar
Secretes and propels mucus
Has cilia and goblet cells
Looks multilayered, but all cells touch the basement membrane
Has nuclei at several layers
Found in the respiratory tract
Describe stratified squamous epithelium
The most widespread epithelium in the body
Deepest layers undergo continuous mitosis
Daughter cells push toward the surface and become flatter as they migrate upward, and the top layer is exfoliated
Name and describe the two types of stratified squamous epithelium
1) Keratinized stratified squamous epithelia
Resists abrasion; retards water loss through skin; resists penetration by pathogenic organisms.
Top layer of cells are dead.
Locations: epidermis; palms and soles heavily keratinized
2) Non-Keratinized stratified squamous epithelia
Resists abrasion and penetration of pathogens
Top layer of cells is not dead.
Locations: tongue, oral mucosa, esophagus, and vagina
Name the two main types of stratified epithelia. Can these be broken down into more types?
Stratified squamous epithelia and transitional epithelia. There are two types of stratified squamous epithelia: keratinized and non-keratinized.
Describe transitional epithelia and where it’s located
A type of stratified epithelia that permits stretching (distension); surface cells change from round to flat when stretched
Locations: ureter and urinary bladder
Describe the properties that most connective tissues have in common.
-Their cells occupy less space than matrix (usually there’s a large amount of extracellular matrix)
-Most of their cells are not in direct contact with each other
-They have a highly variable vascularity
(Loose connective tissues have many blood vessels whereas cartilage has few or no blood vessels)
What is the most diverse and abundant type of tissue
Connective tissue
Discuss the types of cells found in connective tissue.
1) Fibrous Connective Tissue (Connective Tissue Proper)
Made up of fibers (collagen, reticular, and elastic fibers) and ground substance of the matrix produced by fibroblasts.
2) Adipose Tissue
Adipocytes (fat cells) contain a large amount of space reserved for storing fats.
3) Cartilage
Chondroblasts form the matrix, which is then occupied by chondrocytes (cartilage cells)
4) Bone (Osseous tissue)
Osteoblasts form the matrix, which is then occupied by osteocytes.
5) Blood
Made up of plasma, platelets, WBCs, and RBCs.
What are the two main types of fibrous connective tissue? Can they be broken down into further categories.
Loose and dense connective tissue are the two main types. The two types of loose fibrous connective tissue are areolar and reticular. The two types of dense connective tissue are dense regular and dense irregular
Define and describe areolar tissue. Also, where is it found?
- One of the two types of loose connective tissue, which is a type of fibrous connective tissue.
- All 3 fibers/ 6 total cell types are found; loosely organized; abundant blood vessels; lots of empty space.
- Mostly collagenous, but elastic and reticular also present
- Wraps & cushions organs; underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels
- Fibers run in random directions
- Found in tissue sections from almost every part of the body
- Surrounds blood vessels and nerves
- Nearly every epithelium rests on a layer of areolar tissue
- Blood vessels provide nutrition to epithelium and waste removal
- Ready supply of infection-fighting leukocytes that move about freely in areolar tissue
Define and describe reticular tissue. Also, where is it found?
- One of the two types of loose connective tissue, which is a type of fibrous connective tissue.
- Mesh of reticular fibers and fibroblasts
- Forms supportive framework for lymphatic organs
- Found in lymph nodes, spleen, thymus, and bone marrow
Define and describe dense regular tissue
- One of the two types of dense connective tissue, which is one of the types of fibrous connective tissue.
- Densely packed, parallel collagen fibers
- Tendons attach muscles to bones and ligaments hold bones together
Define and describe dense irregular tissue
- Dense, randomly arranged, collagen fibers
- Withstands unpredictable stresses
- Locations: reticular layer of dermis; organ capsules
Describe adipose tissue
- A type of connective tissue
- Space between adipocytes occupied by areolar tissue, reticular tissue, and blood capillaries.
- The quantity of stored triglyceride and the number of adipocytes are quite stable in a person.
- Fat is recycled continuously; new triglycerides synthesized while old molecules hydrolyzed and released to blood
- Functions: Energy storage, insulation, cushioning
- Fat is the body’s primary form of energy storage.
Describe cartilage
Stiff connective tissue with flexible matrix; chondroblasts produce the matrix that will trap them in lacunae (cavities) and become chondrocytes.
Contains reserve population of chondroblasts
List and describe the 3 types of cartilage and where they can be found
1) Hyaline cartilage
Clear, glassy appearance because of fineness of collagen fibers
Surrounded by perichondrium
Locations: articular cartilage, costal cartilage, respiratory cartilage, fetal skeleton
2) Elastic cartilage
Contains abundant elastic fibers; covered with perichondrium
Provides flexible, elastic support
Locations: external ear and epiglottis
3) Fibrocartilage
Contains large bundles of collagen fibers; no perichondrium.
Resists compression and absorbs shock
Locations: pubic symphysis, menisci of knee, and intervertebral discs
Describe bone (osseous tissue)
Has a hard calcified matrix with collagen fibers; made by osteoblasts who build and become osteocytes in lacunae. A type of connective tissue
Describe the two types of bone (osseous tissue)
1) Spongy bone
Porous appearance with visible holes.
2) Compact bone
Compact bone is arranged in cylinders that surround central canals that run longitudinally through shafts of long bones
Describe blood
-A fluid connective tissue
-Transports cells and dissolved matter from place to place
-Plasma—blood’s ground substance
Formed elements—cells and cell fragments:
-Erythrocytes—red blood cells (RBCs)
-Leukocytes—white blood cells (WBCs)
-Platelets—cell fragments involved in clotting
Explain what distinguishes excitable tissues from other tissues.
They have the ability to respond to stimuli by changing membrane potential.
Name the cell types that compose nervous tissue.
Neurons and neuroglia.
Identify and describe the major parts of a nerve cell.
1) Neurosoma (cell body) Contains nucleus & other organelles Controls protein synthesis 2) Dendrites Multiple short, branched processes Receive signals from other cells Transmit messages to neurosoma 3) Axon (nerve fiber) Sends outgoing signals to other cells Can be more than a meter long
Name the three kinds of muscular tissue and describe them
1) Skeletal:
Long thin cells called muscle fibers; multinucleate
Most skeletal muscles attach to bone
Striations—alternating dark and light bands
They only type of muscle that is voluntary, meaning conscious control over skeletal muscles.
2) Cardiac:
Cardiomyocytes are branched, shorter than skeletal muscle fibers; uninucleate
Intercalated discs join cardiomyocytes end to end
Provide electrical and mechanical connection
Striated and involuntary (not under conscious control)
3) Smooth:
Short, fusiform myocytes; uninucleate
Non-striated and involuntary
Most is visceral muscle—making up parts of walls of hollow organs
Define cell junctions and describe what they do
Cell junctions are connections between two cells; most cells are anchored to each other through a cell junction or their matrix
Cells communicate with each other, resist mechanical stress, and control what moves through the gaps between them
List and describe the 3 types of cell junctions
1) Tight junctions:
Seals off intercellular space, making it difficult for substance to pass between cells
Found in the epidermis, stomach, and small intestines
2) Desmosomes
A type of cell junction that keeps cells from pulling apart—resist mechanical stress.
Found in cardiac muscle, the uterine cervix, and the epidermis
3) Gap junctions
Formed by ring-like connexons; the cells now share part of their cell membrane.
Ions, nutrients, and other small solutes pass between cells
Found in cardiac and smooth muscle, embryonic tissue, lens and cornea
Describe the two main kinds of glands
1) Exocrine glands: maintain their contact with surface of epithelium by way of a duct
Their surfaces can be external (examples: sweat, tear glands) or internal (examples: pancreas, salivary glands)
Classified by duct shape and gland shape.
2) Endocrine glands: have no ducts; secrete hormones directly into blood
Examples: thyroid, adrenal, and pituitary glands.
Describe unicellular glands and give examples
Found in an epithelium that is predominantly nonsecretory; can be exocrine or endocrine
Examples: mucus-secreting goblet cells in trachea or endocrine cells of stomach
Define a gland and describe its typical anatomy
- A gland is defined as a cell or organ that secretes substances for use elsewhere in the body or releases them for elimination from the body
- They are usually composed of epithelial tissue with a connective tissue framework and capsule
Name and describe the three different modes of glandular secretion.
1) Merocrine
Uses vesicles that release their secretion by exocytosis.
Used by eccrine glands.
2) Apocrine
Lipid droplet covered by membrane and cytoplasm buds from cell surface
Mode of milk fat secretion by mammary gland cells
3) Holocrine
Cells accumulate a product until they disintegrate (entire cell dies and is secreted, hence why these glands’ substances are oily)
Secrete a mixture of cell fragments and synthesized substances
Ex: sebaceous glands of hair and skin, eyelid glands.
Describe the types and composition of the body’s membranes.
1) Cutaneous membrane (the skin)
Largest membrane in the body
Stratified squamous epithelium (epidermis) resting on a layer of connective tissue (dermis)
Relatively dry layer serves protective function
2) Mucosal membranes
Layers consists of epithelium, areolar tissue (lamina propria), and smooth muscle (muscularis mucosa)
An internal membrane that lines cavities/passages that open to the external environment
Produces mucus (thicker, stickier)
This membrane can be found in 4 organ systems: reproductive, digestive, respiratory, and urinary.
3) Serous membranes
Composed of simple squamous epithelium resting on a layer of areolar tissue
Internal membrane; lines cavities with no connection to the outside
Produces serous fluid
4) Membranes made of only epithelium:
Anterior surfaces of cornea and lens of eye
5) Membranes made of only connective tissue:
Dura mater (meninges), synovial membranes, periosteum, perichondrium
Name and describe the modes of tissue growth.
1) Hyperplasia: growth through cell multiplication
2) Hypertrophy: enlargement of preexisting cells
Examples: muscle growth through exercise, accumulation of body fat
3) Neoplasia: development of a tumor (neoplasm)
Tumor can be benign or malignant
Composed of abnormal, nonfunctional tissue
Name and describe the ways the body repairs damaged tissues.
1) Regeneration: replacement of dead or damaged cells by the same type of cell as before
Restores normal function
Examples: repair of minor skin or liver injuries
2) Fibrosis: replacement of damaged cells with scar tissue
Scar holds organs together, but does not restore function
Examples: repair of severe cuts and burns, scarring of lungs in tuberculosis
List the functions of the skin and relate them to its structure.
1) Resistance to trauma and infection:
- Keratin
- Dermacidin & defensins
- Acid mantle acts as an antimicrobial barrier.
- There are very few spaces between cells in the epidermis to protect against trauma and infection.
2) Other barrier functions
- Water (protects against dehydration): The stratum corneum is a layer of dead cell membranes, which provides a layer of protection against water.
- UV radiation: melanin aids in UV protection
- Harmful chemicals
3) Vitamin D synthesis
- Skin carries out first step; Liver & kidneys complete process
4) Sensation receptors
- Touch, temperature, pressure, vibration, tickle, itch, and pain sensations
5) Regulation of body temperature
- Thermoreceptors
- Vasoconstriction/vasodilation; if you are too warm, cutaneous blood vessels vasodilate
- Perspiration
6) Nonverbal communication
- Facial expressions
- The color of skin based on factors such as blood flow/ hemoglobin and carotene can display signs of illness without verbal communication.
Describe the histological structure of the epidermis, dermis, and subcutaneous tissue.
1) The epidermis consists of keratinized stratified squamous epithelial tissue
2) The dermis consists of two layers:
- Papillary layer: A thin layer of areolar connective tissue
- Reticular layer: A thicker layer of dense irregular connective tissue.
3) Subcutaneous tissue: Consists primarily of adipose connective tissue, but also contains areolar connective tissue.
Describe the difference between thick and thin skin.
Unlike thin skin, thick skin does not contain hair follicles and it has an extra thin white/clear epidermal layer that is not present in thin skin called the stratum lucidum. This causes dermal papillae to be more pronounced in thick skin.
Describe the normal and pathological colors that the skin can have
1) Cyanosis: blueness due to oxygen deficiency
- Oxygen deficiency is usually due to events that cause respiratory distress. This includes things such as drowning, severe asthma attacks, lung failure, pertussis in infants, choking, etc.
2) Erythema: redness due to increased blood flow to skin.
- Increased blood flow to the skin can be caused by injuries such as heat burns, sunburns, consumption of alcohol, or strong emotions such as embarrassment or anger.
3) Pallor: paleness due to decreased blood flow to skin
- Decreased blood to the skin often happens during or immediately prior to syncope or during illness. Malnutrition can also be a cause of pallor.
4) Albinism: milky white skin and blue-gray eyes due to genetic lack of melanin synthesizing enzyme
- This is only due to genetic mutations and cannot develop during a person’s lifetime after birth.
5) Jaundice: yellowing due to bilirubin in blood (can be caused by compromised liver function)
- Often seen in newborn babies or those with liver failure.
6) Hematoma: bruising (clotted blood under skin)
- Usually happens due to blunt force to the skin
Describe the basic structure of a hair and its accessory structures (piloerector muscle, etc.)
1) Bulb: Contains matrix cells (mitotically active cells). Located beneath the surface of the skin and is wider than the rest of the hair.
2) Root: the remainder of the hair in the follicle
Located beneath the surface of the skin and is just above the bulb.
3) Shaft: the portion of the hair that’s above the skin surface
4) Three layers of a hair can be seen in a cross section: Medulla (core), Cortex, Cuticle (outer layer)
5) Hair receptors: Sensory nerve fibers that are entwined with follicles that detect hair movement
6) Piloerector muscle: Smooth muscle that attaches the follicle to dermis; contracts to make hair stand on its end, which causes goose bumps
Discuss the basic functions of hair.
1) Protection: The hair on your scalp provides your head with more protection against sunburns.
2) Light touch: Hair helps you sense light touch due to the presence of hair receptors.
3) Heat retention: The hair on your head provides an extra layer to trap warm air.
4) Excretion: Sebaceous glands found on hair follicles excrete sebum, which helps keep skin and hair from drying out.
Describe the basic structure and function of nails.
Nails are clear, hard derivatives of stratum corneum. They’re composed of thin, dead cells packed with hard keratin.
Provides the tops of our fingertips and toes with an extra layer of protection.
Name two types of sweat glands, and describe the structure and function of each
1) Merocrine sweat glands
- Most numerous type of skin glands
- The gland’s duct opens to the surface of the skin
- Regulates body temperature by allowing for perspiration
2) Apocrine sweat glands
- Found in the regions of the groin, anal region, axilla, areola, and beard (males)
- These glands are inactive until puberty; responds to stress and sexual stimulation
- Ducts lead to nearby hair follicles
- Believed to secrete pheromones
Describe the location, structure, and function of sebaceous glands.
Most sebaceous glands open into a hair follicle, meaning they aren’t present in thick skin.
They utilize a holocrine secretion style and secrete sebum, which is an oily secretion that keeps skin and hair from becoming dry, brittle, and cracked. It also inhibits the growth of bacteria & fungi (ringworm)
Name some other cutaneous glands
1
1) Ceruminous glands in external ear canal
- Modified apocrine sweat glands
- Forms earwax (cerumen)
2) Mammary Glands
- Milk-producing modified apocrine sweat glands that develop only during pregnancy
- Two rows of mammary glands can be found in most mammals
Describe the three most common forms of skin cancer.
1) Basal cell carcinoma
- Most common form of skin cancer, but the least malignant
- Most often on the head, neck, and hands
- Most common in fair-skinned people and the elderly
- Forms from cells in stratum basale
- Lesion is small, shiny bump with central depression and beaded edges
2) Squamous cell carcinoma
- May metastasize if not removed; tends to metastasize to lymph nodes and may become lethal. However, the chance of recovery is good with early detection and surgical removal
- Arises from keratinocytes of stratum spinosum
- Lesions usually found on the scalp, ears, lower lip, or back of the hand
- They typically have a raised, reddened, scaly appearance later forming a concave ulcer
3) Melanoma
- Least common (less than 5% of skin cancers) but very malignant. Can be successfully removed if caught early, but if it metastasizes it is usually fatal
- Skin cancer that arises from melanocytes
- Greatest risk factor: familial history of malignant melanoma
- Highest incidence in men, redheads, and people who had severe sunburn as a child
Describe melanomas
Least common (less than 5% of skin cancers) but very malignant. Can be successfully removed if caught early, but if it metastasizes it is usually fatal
Skin cancer that arises from melanocytes
Greatest risk factor: familial history of malignant melanoma
Highest incidence in men, redheads, and people who had severe sunburn as a child
Describe basal cell carcinoma
Most common form of skin cancer, but the least malignant
Most often on the head, neck, and hands
Most common in fair-skinned people and the elderly
Forms from cells in stratum basale
Lesion is small, shiny bump with central depression and beaded edges
Describe squamous cell carcinoma
May metastasize if not removed; tends to metastasize to lymph nodes and may become lethal. However, the chance of recovery is good with early detection and surgical removal
Arises from keratinocytes of stratum spinosum
Lesions usually found on the scalp, ears, lower lip, or back of the hand
They typically have a raised, reddened, scaly appearance later forming a concave ulcer
Describe the three classes of burns.
1) First-degree burn
- Involves only the epidermis and heals in days.
2) Second-degree burn
- A partial-thickness burn; involves part of dermis
- May appear red, tan, or white; often blistered and painful
- Takes two weeks to several months to heal and may leave scars
3) Third-degree burn
- A full-thickness burn; involves epidermis, all of dermis, and often some deeper tissues
- Often requires skin grafts
- Typically requires fluid replacement, infection control, and supplemental nutrition
Name the tissues and organs that compose the skeletal system.
Major organs: Bones.
Major tissues: Bones are made up of bone tissue, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue
Describe the major functions of the skeletal system and give examples
1) Support: Limb bones and vertebrae support the body; jaw bone supports the teeth; bones support viscera
2) Protection: Cranial bones protect the brain, vertebrae protect the spinal cord, ribs protect the heart and lungs, etc
3) Movement: Allows for movement of limbs and breathing (requires action of muscles on bones).
4) Electrolyte balance: Helps regulate calcium & phosphate levels
5) Acid–base balance: Buffers the blood against large pH changes by altering phosphate and carbonate salt levels
6) Blood formation: Red bone marrow produces red blood cells.
Distinguish between bones as a tissue and as an organ.
Bones (organs) have multiple types of tissue; each individual bone in your body is a separate organ.
One of the types of tissue found in bones (organs) is called bone tissue, also called osseous tissue.
Describe the types of bones classified by shape and give examples
1) Flat bones: cranial bones, sternum, ribs, scapula, hip.
- These bones are usually for protection
2) Long bones: femur, humerus, radius and ulna, metatarsals, metacarpals, digits of manus and pedal regions, etc
- These bones are usually in appendages, for movement
3) Short bones: carpal (wrist) bones, tarsal (ankle) bones
4) Irregular bones: vertebrae, some skull bones (inner ear bones)
5) Sesamoid (type of short bone): patella
- Sesamoid bones develop in a tendon (or ligament) in response to a need for more leverage.
6) Sutural (wormian) bones
- Sutural bones are the extra bones in the sutures (especially the lambdoid suture) of the skull.
- Everyone has a different number of sutures in their cranium (i.e. some people only have 1, while others may have 4, depending on how their cranium formed).
Identify the internal structural components of compact bone
- The dense outer shell of bone
- Made up of subunits called osteons, which contain:
1) Lamellae - Columns of the matrix (mainly collagen) that are weight bearing
- Run concentric, circumferential, and interstitially
2) Central (Haversian canal) - Contains blood vessels and nerves
3) Perforating (Volkmann’s) canals - Channels that connect blood and nerves from periosteum to the central (Haversian) canal; run transverse or diagonal.
Osteons are made up of what 3 components?
Lamellae, central (haversian) canal, and perforating (volkmann’s) canals
Identify the internal structural components of spongy bone
- A lattice of bone covered with endosteum and an internal honeycomb of trabeculae filled with red or yellow bone marrow
- Trabeculae (thin plates of bone) develop along the bone’s lines of stress.
- Spaces filled with red bone marrow
- Few osteons and no central canals
- Provides strength with minimal weight
Describe and distinguish between the two types of bone marrow.
1) Red marrow
- Contains hemopoietic tissue; produces blood cells.
- Found in almost all bones in children, and found primarily in the axial skeleton of adults.
2) Yellow marrow
- Found in adults
- Stores triglycerides; functions as energy storage.
- Can transform back to red marrow in the event of chronic anemia.
Describe the intramembranous ossification mode of bone formation
- Bone develops within a fibrous connective tissue membrane
- Mesenchymal cells»_space;> osteoblasts»_space;> osteocytes (spongy bone)
- Forms the flat bones of the skull, clavicles, and ossifies the fontanels.
- Most of these bones are remodeled (destroyed and reformed) as we grow to adult size.
- Thickens long bones throughout our lives.
Describe the endochondral ossification mode of bone formation
- Bone forms by replacing hyaline cartilage
- Forms most the bones of the body below the skull (except the clavicle)
- Mesenchyme»_space;turns into» chondroblasts»_space; die and are replaced by»_space; osteoblasts»_space;turn into» spongy bone»_space;turn into» compact bone
Compare and contrast the function of osteoblasts and osteoclasts during bone growth, repair, and remodeling.
- Osteoblasts: create bone
- Osteoclasts: break down bone.
- During bone growth, osteoblasts create bone. –During bone remodeling, osteoclasts break down bone and osteoblasts create bone.
Name and describe the process by which minerals are added to bone tissue.
- Mineral deposition (mineralization): the process in which calcium, phosphate, and other ions are taken from blood and deposited in bone.
- During this process, osteoblasts produce collagen fibers, and the collagen fibers then become encrusted with minerals.
- The first few mineral crystals act as “seed crystals” that attract more calcium and phosphate
Name and describe the process by which minerals are removed from bone tissue.
- Mineral resorption: the process of dissolving bone and releasing minerals into blood
- This process is performed by osteoclasts; they pump hydrogen to extracellular fluid (chloride follows). Hydrochloric acid (pH 4) dissolves bone minerals.
- They also produce an enzyme which digests collagen in an acidic environment.
Describe the role of the bones in regulating blood calcium and phosphate levels.
- When blood calcium or phosphate is LOW, the process of mineral resorption takes place. For example, if blood calcium is low, then some of the calcium stored in the bones will be resorbed into the blood stream.
- When blood calcium or phosphate is HIGH, the process of mineral deposition takes place. For example, if blood calcium is high, then some of the calcium from the blood stream will be deposited into the bones.
Explain the role of calcitriol in regulation of bone physiology and describe its effect
- Calcitriol (aka vitamin D) is a hormone that raises blood calcium levels.
- Mainly, it increases calcium absorption by the small intestine, but it also increases calcium resorption from the skeleton, and weakly promotes kidney reabsorption of calcium ions, so less are lost in urine.
- It’s produced by actions of skin, liver, and kidneys.
- Calcitriol is necessary for bone deposition, so lack of calcitriol results in abnormal softness of bones; in children, this causes rickets, and in adults, this causes osteomalacia.
Explain the role of calcitonin in regulation of bone physiology and describe its effect
- Calcitonin is produced by the thyroid gland and lowers blood calcium levels; its release is triggered by high blood calcium.
- It lowers blood calcium concentration in 2 ways; it inhibits osteoclasts and stimulates osteoblasts.
- It’s important in children, but has a weak effect in adults (except may inhibit bone loss in pregnant and lactating women)
Explain the role of parathyroid hormone in regulation of bone physiology and describe its effect
- Parathyroid hormone is produced by the parathyroid glands, and increases blood calcium; its release triggered by low blood calcium.
- PTH increases blood calcium 4 ways; it stimulates osteoclast population and bone resorption, promotes calcium reabsorption by kidneys, promotes calcitriol synthesis, and inhibits osteoblasts, inhibiting bone deposition
Explain the hormonal regulation of skeleton growth.
- Epiphyseal plate activity is stimulated by Human Growth Hormone (hGH); hGH stimulates growth at the epiphyseal plates in children.
- Estrogen has a stronger effect on skeleton growth than testosterone; both of those hormones begin to affect bone growth during puberty, and they differentiate the male and female skeleton.
- Males typically continue to grow for a longer period of time than females.
- At least 20 or more hormones, vitamins, and growth factors affect osseous tissue.
- Anabolic steroids administered during childhood/ adolescence can also prematurely stop bone growth.
Describe the bone disease ostoporosis
- The most common bone disease
- Affects spongy bone the most since it is the most metabolically active
- Subject to pathological fractures of hip, wrist, and vertebral column
- Kyphosis (widow’s hump): deformity of spine due to vertebral bone loss
- Complications of loss of mobility are pneumonia and thrombosis
- Estrogen maintains bone density in both sexes; inhibits resorption by osteoclasts
- Postmenopausal white women are at the greatest risk; white women begin to lose bone mass as early as age 35. By age 70, their average loss is 30% of bone mass.
- Osteoporosis also seen in young female athletes with low body fat causing them to stop ovulating and decrease estrogen secretion
- Risk factors: race, age, gender, smoking, diabetes mellitus, diets poor which are poor in: calcium, protein, vitamins C and D
- Treatments: Estrogen replacement therapy (ERT) (slows bone resorption, but increases risk of breast cancer, stroke, and heart disease); PTH derivative can also be used as a treatment but can cause bone cancer; certain medications destroy osteoclasts.
- However, best treatment is prevention: exercise and a good bone-building diet between ages 25 and 40
Describe the bone disease osteomalacia
Caused by low levels of calcitriol (vitamin D) in adults; leads to abnormally soft bones. This is because calcitriol is necessary for bone deposition.
Describe the bone disease Ricket’s
Caused by low levels of calcitriol (vitamin D) in children; leads to abnormally soft bones. This is because calcitriol is necessary for bone deposition.
Describe the bone disease osteogenesis imperfecta
A deficit in collagen deposition.
Name and describe the types of fractures.
- Non-displaced: A fracture where the bones remain aligned.
- Displaced: A fracture where the bones become misaligned.
- Comminuted: A fracture in which the bone breaks into several pieces
- Greenstick: An incomplete fracture in which the bone is bent; occurs most often in children.
Explain the ways in which a fracture can be repaired.
- Closed reduction: A procedure in which bone fragments are manipulated into their normal positions without surgery
- Open reduction: Involves surgical exposure of the bone and the use of plates, screws, or pins to realign the fragments
- Cast: normally used to stabilize and immobilize healing bone
Explain how the body heals fractures
The body repairs fractures by forming a hematoma, then a soft callus, then a hard callus, then bone remodeling.
Predict factors or situations affecting the skeletal system that could disrupt homeostasis.
- Lack of vitamin D in your diet could lead to osteomalacia, disrupting homeostasis.
- Radiation therapy can cause damage to red bone marrow, which can lead to decreased blood cell production, which can lead to disruption of homeostasis.
Predict the types of problems that would occur in the body if the skeletal system could not maintain homeostasis.
Lack of homeostatic control causes illness, injury, or death.
Describe the axial skeleton and list the general bone structures contained within it
The axial skeleton has 80 named bones, and includes structures such as the skull, vertebrae, sternum, ribs, sacrum, and hyoid.
Describe the appendicular skeleton and list the general bone structures contained within it
The appendicular skeleton has 126 named bones, and includes structures such as the pectoral and pelvic girdles and upper and lower extremities (limbs).
Name the cranial bones and describe their locations
There are 8 cranial bones; two parietal, two temporal, frontal, occipital, sphenoid, and ethmoid.
The parietal bones are located at the apex of the head.
The frontal bone is located at the front of the head.
The temporal bones are located on the sides of the head (this is where the ears are located)
The sphenoid bone makes up the back of the eye socket
The ethmoid bone makes up the medial part of the eye socket.
Name the facial bones and describe their locations
There are 14 facial bones; two nasal, 2 maxilla, 2 lacrimal, 2 zygomatic, 2 inferior nasal concha, 2 palatine, vomer, and mandible.
The nasal bones are located towards the top of the nose.
The two maxillary bones are located superior to both the upper and lower teeth and inferior to the nose
The two zygomatic bones are located on either side of the face (often referred to as ‘cheekbones’)
The two lacrimal bones are located on the medial side of the eye sockets (superficial to the ethmoid bone).
The two inferior nasal concha are located on both lateral sides of the vomer.
The vomer makes up the middle of the nose and separates the left nostril from the right.
The mandible makes up the chin and lower jaw (inferior to the maxillary bone and teeth).
Describe the hyoid bone
This bone is located deep and inferior to the mandible, and it does not articulate with any other bones.
Describe the naming conventions of bone markings
- As a general rule, anything named as a process, tubercle, tuberosity, trochanter, condyle, or crest are projections of bone and are generally used as attachment sites for muscles or ligaments.
- Anything named as a foramen is a hole typically used for blood vessels or nerves.
- Anything named as a fissure is a slit-like narrow opening.
- Anything named as a notch is an indentation or large groove in a bone, and anything named a fossa is a shallow depression.
Describe the features/markings of the occipital bone (2)
- The occipital bone contains the foramen magnum, which is a hole in the occipital bone where the brainstem enters.
- The occipital condyles are round kidney bean shapes around the foramen magnum, which is where the skull articulates with vertebrae (this is what gives the us the ability to nod our heads vertically)
Describe the features/markings of the temporal bone (4)
- The temporal bone contains the external acoustic meatus, which is the hole of the ear canal.
- The mastoid process is a rather large bony projection that is located behind the ear.
- The styloid process is a small bony projection that serves as an anchor point for muscles associated with the tongue and larynx.
- The mandibular fossa is a shallow depression located just slightly anterior to the styloid process.
Describe the features/markings of the sphenoid bone (5)
- The majority of the sphenoid bone is made up of the greater and lesser wings (the lesser wing is anterior to the greater wing).
- The sella turcica is where the brain sits.
- The superior orbital fissure is a spike/triangular shaped hole, and allows certain nerves to enter the orbit.
- The optic canal lets the optic nerve into the orbit.
Describe the features/markings of the ethmoid bone (3)
- The ethmoid bone has cribriform plates, the holes of which are what allow nerves entry to the nasal cavity.
- The olfactory foramina lets bundles of nerve fibers of the olfactory nerve enter the nasal cavity. -The meninges anchor to the crista galli.
List the bones that contain the paranasal sinuses.
The frontal, sphenoid, ethmoid, and maxillary bones.
Define and describe the purposes of fontanelles in a newborn skull
Fontanelles in the newborn skull are dense connective tissue membrane-filled spaces
(soft spots); they are unossified at birth but close early in a child’s life. They have two purposes: to allow the fetal skull to pass through the birth canal, and to allow rapid growth of the brain during infancy.
List the most common fontanelles found in the newborn skull
The most common fontanelles are the sphenoidal (aka anterolateral fontanel), the mastoid (aka posterolateral fontanel), the anterior fontanel, and the posterior fontanel.
Describe the general features of the vertebral column
The vertebral column typically consists of 7 cervical vertebrae (C1 is the atlas and C2 is the axis), 12 thoracic vertebrae, 5 lumbar vertebrae, sacrum (5, fused), and coccyx (3-5, fused).
Describe the general features of vertebrae
Typical vertebra consist of a body, vertebral foramen (where the spinal cord goes), and a spinous process (excluding the atlas).
Describe the general differentiating features of cervical, thoracic, and lumbar vertebrae.
The cervical vertebra have a transverse foramen to let the vertebral arteries travel up to the head and neck.
The thoracic vertebrae typically each attach to a pair of ribs.
The lumbar vertebrae typically have very large bodies.
Describe the structure of the intervertebral discs and their relationship to the vertebrae.
Intervertebral discs are made of fibrocartilage with a pulpy center and are located between each vertebrae, and their purpose is to absorb vertical shock and allow for the vertebral column to move.
Describe herniated discs
If the nucleus pulposus of an intervertebral disc herniates, it puts pressure on the nerves and causes pain.
Describe the primary normal curvatures of the vertebral column.
Primary curvatures: thoracic and sacral curves, which form during fetal development
Describe the secondary normal curvatures of the vertebral column
Secondary curvatures: cervical and lumbar curves; the cervical curve forms when infant raises head at 4 months, and the lumbar curve forms when an infant sits up & begins to walk.
Describe how the shape of the spine changes during the first 3 years of life.
The spine has a C-shaped curve at birth (convex) and is S-shaped past the age of 3 years.
Describe the three abnormal curvatures of the vertebral column.
Kyphosis (hunchback): exaggerated thoracic curvature, usually from osteoporosis, osteomalacia, spinal tuberculosis, or weightlifting and/or wrestling from a young age.
Lordosis (swayback): exaggerated lumbar curvature
Scoliosis: lateral bending of the spinal column; the most common abnormal curve, and is often seen in adolescent girls.
Describe the anatomy of the sternum and ribs and how the ribs articulate with the thoracic vertebrae.
Ribs 1-7 are true ribs (their cartilage directly connects to the sternum) 8-12 are false ribs (they indirectly connect to the sternum), and ribs 11-12 are floating ribs (they do not connect to the sternum). Each thoracic vertebrae articulates with a pair of ribs.
Identify the features of the scapula
Scapular spine, acromion process, coracoid process, glenoid cavity, supraspinous fossa, infraspinous fossa, subscapular fossa.
Scapula: Describe the scapular spine
The scapular spine is a horizontal line of protruding bone along the posterior side of the scapula.
Scapula: Describe the acromion process
The acromion process is a bulbous end found at the lateral side of the scapular spine.
Scapula: Describe the coracoid process
The coracoid process is a protrusion similar in appearance to the acromion process, but on the anterior side of the scapula.
Scapula: Describe the glenoid cavity
The glenoid cavity is a groove situated between the acromion and coracoid processes.
Scapula: Describe the supraspinous fossa
The supraspinous fossa is a shallow indentation superior to the scapular spine on the posterior side.
Scapula: Describe the infraspinous fossa
The infraspinous fossa is a shallow indentation inferior to the scapular spine on the posterior side.
Scapula: Describe the subscapular fossa
The subscapular fossa is a shallow indentation inferior to the scapular spine on the anterior side.
List the proximal and distal features of the humerus
Proximal end: head, surgical neck, anatomical neck, greater tubercle, lesser tubercle, intertubercular groove, deltoid tuberosity
Distal end: olecranon fossa, coronoid fossa, radial fossa, capitulum, trochlea, medial epicondyle, lateral epicondyle.
Humerus: Describe the head, surgical neck, and anatomical neck
- The head of the humerus is a the rounded side of the proximal end, and is pointed medially.
- The surgical neck is the thinner area below the anatomical neck of the proximal end of the humerus where the humerus is cut during amputations.
- The anatomical neck is located just inferior to the head of the humerus on the proximal end; it is where the head of the humerus ends.
Humerus: Describe the greater tubercle and lesser tubercle
The greater tubercle is a small, rounded projection that is located on the lateral side of the humerus on the proximal end.
The lesser tubercle is a small, rounded projection that is located on the medial side of the humerus on the proximal end.
