Unit 1: Intro to human body Flashcards
1
Q
Define Anatomy and Physiology
A
Anatomy is the science of body structures and the relationships among them. Physiology is the science of body functions
2
Q
Six levels of structural organization
A
Chemical, Cellular, Tissue, Organ, system, and Organism
3
Q
Six important life processes
A
Metabolism, Responsiveness, Movement, Growth, Differentiation, and Reproduction
4
Q
Important life process: Define Metabolism. (Catabolism and Anabolism)
A
The sum of all chemical processes that occur in the body. Catabolism - the break down of complex substances into simpler components. anabolism - the building up of the complex chemical substances form small, simpler components.
5
Q
Important life process: Define Responsiveness (Nerve cells and Muscle cells)
A
The body’s ability to detect and respond to changes. Nerve cells - responds by generating electrical signals known as nerve impulses. Muscle cells - responds by contracting to force the body to move.
6
Q
Important life process: Define Movement
A
Motion of the whole body, individual organs, single cells, and even tiny structures inside cells.
7
Q
Important life process: Define Growth.
A
Increase in body size that results from an increase in the size of existing cells, and increase in the number of cells, or both.
8
Q
Important life process: Define Differentiation. (Stem cells)
A
Development of a cell from an unspecialized to a specialized state. Stem cells - pre cursor cells, which can divide and give rise to cells that undero differentiation.
9
Q
Important life process: Define Reproduction.
A
Refers either to:
- the formation of new cells occur for tissue growth, repair, or replacement through cell division.
- the production of a new individual through fertilization of an ovum by a sperm cell.
10
Q
Define Homeostasis.
A
The maintenance of a relatively stable conditions in the body’s many regulatory systems.
11
Q
Define Intercellular, Interstitial, and Extracellular fluids.
A
Intercellular fluid - fluid within cells
Extracellular fluid - fluids outside the cells
Interstitial fluid - the extracellular fluid that fills the narrow spaces between cells of tissue.
12
Q
What are the different types of Extracellular fluids and what they do?
A
Blood plasma - RBCs
Lymph - WBCs
Cerebrospinal fluid - Fluid around the brain and the spine
Aqueous humor/vitreous body - fluid that keeps the eye its shape
13
Q
What two systems control homeostasis?
A
The nervous and endocrine system
14
Q
Define Feedback loop. (Controlled variable and stimulus)
A
A cycle of events in which the status of a body conditions is monitored, evaluated, changed, re-monitored, and re-evaluated. controlled valuable - monitored conditions such as body temp., BP, and/or BG. Stimulus - Any disruption that changes a controlled conditions
15
Q
What are the feedback loop components? and explain.
A
Receptor - monitors changes in a controlled condition and sounds input to a control centre. This pathway is called an afferent pathway. The input in the form of nerve impulses or chemical signals.
Control Centre - Processes the information from the receptor and activate effectors when needed. This pathway is called an efferent pathway, since information flows away from the control centre.
Effector - body structures that receives output from the control centre and produces a response or effect that changes the controlled condition.
16
Q
Define Negative Feedback system.
A
This system reverses a change in a controlled conditions. Negative feedback maintains homeostasis.
17
Q
Define Positive Feedback system.
A
This system tends to strengthen or reinforce a change in the body’s controlled conditions.
18
Q
Describe the three body positions.
A
Anatomical positions - Any region or part of the human body assume that it is in a standard position or reference. Standing up right and facing forwards with each arm hanging on either side and their palms facing forward.
Prone - Body lying facedown.
Supine - Body laying face up.
19
Q
Describe the five anatomical planes.
A
Sagittal plane/Midline - vertical plane that divides the body or organ into right and left sides.
Frontal plane - divides the body or an organ into anterior and posterior portions.
Transverse plane - cross sectional or horizontal plane. Divides the body or organ into superior and inferior portions.
Oblique plane - passes through the body or organ at an angle.
20
Q
Define Anatomical section.
A
A cut of the body or one of its organs made along one of the anatomical plane.
21
Q
Name the four body cavities.
A
Cranial cavity - cranial bones that contains the brain.
Vertebral canal - The bones of the back bone and spine and contains the spinal cord.
Thoracic cavity - The major body cavities of the trunk. formed by the ribs, muscle, sternum, and the thoracic portion.
Abdominopelvic cavity - Divided into the abdominal and pelvic cavity.
22
Q
What is in the thoracic cavity and what is it covered with?
A
It contains the pericardial cavity which contains the heart and great vessels, and is wrapped in a serous membrane called the pericardium. It also contains the lungs, which is split into two cavities called lobes, these are covered in a serous membrane called pleura. In the thoracic cavity, it contains the heart, lungs, trachea, esophagus, and the great vessels.
23
Q
What is in the abdominopelvic cavity and what is it covered with?
A
Divided into two portions with no walls. The abdominal cavity contains the stomach, liver, spleen, kidneys, small intestines, and most of the large intestines and the gallbladder. The pelvic cavity contains the bladder, internal reproductive organs and portions of the large intestines. The abdominopelvic cavity is covered in the serous membrane Peritoneum.
24
Q
What does Viscera mean?
A
The organs inside the thoracic, abdominal, and pelvic cavities.
25
This time be the main character of your story and go beyond what you're named to be.
26
Define chemistry. (Matter, mass, and weight)
Chemistry is the science of the structure and interactions of matter. Matter - anything that occupies space. Mass - the amount of matter in any object, which does not change. Weight - the force of gravity acting on matter, and does change.
27
Define the three stats of matter.
Solid - compact and have a definite shape and volume.
Liquids - have a definite volume and assume the shape of the container.
Gases - neither have a definite shape or volume.
28
What are the four major chemicals?
Oxygen - part of water and many organic molecules. Used to generate ATP
Carbon - Forms the backbone chains and the rings of all organic molecules.
Hydrogen - constituents of water and most organic molecules. Ionized form make the body fluid more acidic.
Nitrogen - components of all protein and nucleic acid
29
What are the three lesser elements?
Calcium - contributes to hardness of bones and teeth. Ionized form needed for blood clotting, and for contraction of muscles.
Phosphorus - ionized form is the most plentiful cation in the intercellular fluid. Needed to generate action potential.
30
Define Atom and what does is compose of?
The smallest units of matter that retain the properties and characteristics of the element. Particles that composes an atom is called Subatomic particles.
31
Name the structures of an atom.
Nucleus - the dense central core
Protons and neutrons - located in the nucleus, protons are positively charged, and neutrons are uncharged.
Electrons - surrounds the nucleus and is negatively charged.
32
Where do electrons move about in? And how many can it hold?
Electrons move about within certain regions around the nucleus called electron shells. 1st shell - max 2. 2nd shell - max 8. 3rd shell - max 18.
33
Define atomic number and mass number.
The number of protons in the nucleus is an atoms atomic number. The mass number of an atom is the sum of its protons and neutrons.
34
Define isotopes and radioactive isotopes.
Isotopes are atoms of an element that have a different numbers of neutrons and therefore different mass numbers. Radioactive isotopes are unstable from of a chemical element that releases radiation as it breaks down.
35
Define Ions.
An atom that has a positive or negative charge because it has unequal number os protons and electrons. If an atom either gives up or gains electrons, it becomes an ion.
36
Define Ionization and how it relates to molecules.
The process of giving up or gaining electrons when two or more atoms share electrons, the resulting combination is a molecule.
37
Define Compounds.
A substance that contains atoms of two or more different elements.
38
Define Free radicals.
An atom or group of atoms with an unpaired electron in the outermost shell. Having an unpaired electron makes a free radical unstable, highly reactive, and destructive.
39
Define Chemical bonds.
The forces that hold together the atoms of a molecule or compound.
40
Why is the valence shell important in bonding? And how does it bond?
The likelihood that an atom will form a chemical bond with another atom depends on the number of electrons in its outermost shell called the valence shell.
An atom with a valence shell holding eight electrons is chemically stable, meaning it is unlikely to form chemical bonds with other atoms. It bonds with other atoms to make its valence shell a total of eight. (Octet rule)
41
Define ionic bonds.
The force of attraction that holds together ions with an opposite charge. (opposites attract)
42
Differentiate between Cations and Anions.
Cations are positively charged ions. Atoms that contain more protons than electrons.
Anions are negatively charged ions. They contain more electrons than protons.
43
Define Electrolytes.
Ionic compound that breaks apart into positive and negative ions in a solution. Named because electrolyte solutions can conduct an electrical current.
44
Define Covalent bonds.
When a covalent bond forms, two or more atoms share electrons rather than gaining or losing them.
45
Differentiate between Non polar and Polar covalent bond.
Non polar covalent bonds are when two atoms share the electrons equally. Polar covalent bond is when sharing of electrons between two atoms is unequal.
46
Define Hydrogen bonds.
Forms when a hydrogen atom with a partial positive charge attracts the partial negative charge.
47
Define surface tension.
A measure of the difficulty of stretching or breaking the surface of a liquid.
48
How does chemical reactions occur? How does it relate to metabolism?
Chemical reactions occurs when new bonds form or old bonds break between atoms, they are the foundation of all life processes. Metabolism refers to all chemical reactions ocuring in the body.
49
Define Energy. What are the two forms of energy?
Energy is the capacity to do work.
Potential energy - energy stored by matter due to its position.
Kinetic energy - energy associated with matter in motion.
50
What is the Law of Conservation of Energy?
Energy can be neither created nor destroyed, it may be converted from one form to another.
51
Differentiate between Endergonic reactions vs. Exergonic reactions.
Endergonic reaction - absorbing energy in the form of work. Non spontaneous
Exergonic reaction - releasing energy in the form of work. Spontaneous.
52
Define Activation energy.
The minimum amount of energy required for a chemical reaction to occur. Concentration and temperature of a particle influence the chance that a collision will occur and cause a chemical reaction.
53
What is a Catalyst?
Catalysts are compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur. The most important catalysts are called enzymes.
54
How does chemical reactions occur? And how does a catalyst help?
Chemical reactions to occur, some particles of matter not only must collide with sufficient force, but must hit one another at precise spots. A catalysts helps to properly orient the colliding particles.
55
What are the 5 types of chemical reactions?
Synthesis, Decomposition, Exchange, Reversible, and Oxidation-reduction reactions.
56
Define Synthesis reactions.
When two or more atoms, ions, or molecule combine to for a new and larger molecule. Synthesis reactions that occur in the body is referred to as Anabolic which requires energy to grow and build (endergonic).
57
Define Decomposition reaction.
Splits up large molecules into smaller atoms, ions, or molecules. The decomposition reaction in our body is called Catabolism-release energy (Exergonic).
58
Define Exchange reaction.
They consists of both synthesis and decomposition reaction. Bonds are both broken and formed and energy is exchanged.
59
Define Reversible reaction.
Some chemical reactions are only one way. In a reversible reaction, the products can revert to their original reactant.
60
Define Oxidation-Reduction reaction.
Reactions that break down food molecules to produce energy. Oxidation refers to the loss of electrons which releases energy. Reduction refers to the gain of electrons.
61
Differentiate between Organic vs Inorganic compounds.
Organic compounds always contain Carbon, usually contains hydrogen and always have covalent bonds. Organic compounds come from living things.
Inorganic compounds usually lacks carbon and are structurally simple. Cannot be used by cells to perform complicated biological functions. Inorganic compounds come from non living things.
62
Why is water an excellent solvent?
Water is the most important and abundant inorganic compounds in all living system. Due to its polarity and ability to form hydrogen bonds, water makes an excellent solvent.
63
Differentiate between Hydrophilic vs. Hydrophobic.
Hydrophilic means they dissolve easily in water, they love water.
Hydrophobic are not very water soluble, and they hate water.
64
Define Hydrolysis.
Decomposition reactions break down large nutrient molecules into smaller molecules by adding water molecules. This type of reactions is called hydrolysis. Hydrolysis reactions enable dietary nutrients to be absorbed into the body.
65
Define Dehydration synthesis reactions.
Two smaller molecules joint to form a larger molecule.
66
Differentiate between heat capacity vs. heat of vaporization.
Water can absorb and release relatively large amount of heat with only a modest change in temperature making water have a high heat capacity.
Water also requires a marge amount of heat to change from a liquid to gas making water have a high heat of vaporization.
67
Define Mixture. Differentiate between solutions, colloids, and suspensions.
A mixture is a combination of elements or compounds that are physically blended together but not chemically bonded.
Solution - have the smallest particles., light can pass through it making it look transparent.
Colloids - Small particles but larger than solution particles and scatter light making it almost see through.
Suspension - May mix with the liquid or suspending medium for sometime. But eventually settles. Not see through.
68
There is no shame in whatever stage you find yourself in
69
Define dissociation in acids, bases and salt.
Dissociate - they separate into ions and becomes surrounded by water molecules.
Acid - a substance that dissociates into one or more hydrogen ions and in one or more anions. Acids are proton donors.
Base - Removes hydrogen ions from a solution. Bases are proton acceptors.
Salt - dissociates into cations and anions, neither a hydrogen ion or hydroxide ions.
70
What are buffers?
Buffer systems functions to convert strong acids and bases into weak acids or bases. The chemical compounds that can convert strong acids or bases into weak ones are called buffers. Buffers either add or remove protons.
71
What are Macromolecules?
Small organic molecules can combine into very larger molecules that are called Macromolecules.
72
Define Functional group.
Determines the chemical activity of an organic molecule.
73
How do Polymers and Monomers relate?
Macromolecules are usually Polymers. A polymer is a large molecule formed by the covalent bonding of many identical or similar small building blocks molecules called monomers. Polymers are formed from multiple monomers connected together.
Monomers - beads
Polymers - necklace
74
Define Isomers.
Molecules that have the same molecular formula (atoms) bur arranged differently.
75
What are Carbohydrates and what is its function?
Carbohydrates include sugar, glycogen, starches, and cellulose. Carbohydrates function mainly as a source of chemical energy needed to drive metabolic reactions. It contains carbon, hydrogen, and oxygen.
76
Define Monosaccharides.
monomers of carbohydrates. A simple sugar that only contains one unit. Simple sugar.
77
Define Disaccharide.
A molecule formed from the combination of two monosaccharides by dehydration synthesis. Simple dugar.
78
Define Polysaccharide. What is the main one in our body?
Each polysaccharide molecule contains tens or hundreds of monosaccharides joined together through dehydration synthesis reaction. They are insoluble in water, and are not sweet.
Glycogen is the main polysaccharide, it is made entirely from glucose monomers.
79
Define Cellulose?
A polysaccharide formed from glucose by plants that cannot be digested by humans.
80
What are lipids? How does it relate to lipoproteins?
They are the second most important group of organic compound. They are known hydrophobics.
To become more soluble in blood plasma, other lipid molecules join with hydrophilic protein molecule. The resulting lipid-protein complexes are caalle lipoproteins.
81
Define Fatty acids. What are the two types of fatty acids?
Fatty acids are the simplest lipid, which are also used to to synthesize triglicerydes and phospholipids. The two types are Saturated fatty acids, which contains only single covalent bonds. There is also unsaturated fatty acids which contains one or more double covalent bonds.
82
Define Triglycerides. What is the difference between fat and oil?
The most plentiful lipid in your body. It contains a single glycerol molecules and three fatty acid molecules. They are used to store unused calories for your body to use later.
A fat is a triglyceride that is a solid at room temperature. An oil is a triglyceride that is a liquid in room temperature.
83
Define Phospholipids.
Makes up the cell membrane. Made our of a phosphate group, a glycerol molecule and two fatty acid chain.
84
What are proteins? What are the monomers of proteins?
Proteins are large molecules that contains carbon, hydrogen, oxygen, and nitrogen. Some contain sulfur. They are largely responsible for the structure of body tissue. Some proteins work to drive muscle contractions.
The monomers of proteins are amino acids.
85
Define Enzymes.
Enzymes are proteins and they are aso catalyst. They speed up most biochemical reactions.
86
What are Antibodies?
They are proteins that defend against invading microbes.
87
How does the body uses amino acids? How is peptide bonds related?
When proteins are digested and broken down, amino acids are left. The body uses amino acids to make proteins. Within a protein, multiple amino acids are linked together by peptide bonds thereby creating a long link. As peptide bonds form, a molecule of water is removed making this a dehydration synthesis reaction.
88
What are Dipeptides and Tripeptides? How are peptide and polypeptides different?
Dipeptide is when two amino acids combine, adding another results in tripeptide. Further additions of amino acids result in the formation of a chainlike peptide (4-9 amino acids) or polypeptide (10-2000 or more amino acids).
89
Explain the process of Denaturation.
If a protein encounters an altered environment, it may unravel and lose its characteristics. This process is known as denaturation. These are proteins that are no longer functional. Some can be reversed, but some are permanent. Like frying an egg.
90
What are the two parts of enzymes?
Apoenzymes is the protein portion and cofactor is the non protein portion.
91
What are the three important properties of enzymes?
Enzymes are highly specific - each particular enzymes binds only to specific substrates.
Enzymes are efficient.
Enzymes are subject to a variety of cellular control - substances within the cell may either enhance or inhibit the activity of a given enzyme.
92
What are Nucleic acids? What are its two varieties?
They are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. A nucleic acid is a chain of repeating monomers called nucleotides.
There is Deoxyribonucleic Acid (DNA) and Ribonucleic Acids (RNA).
93
What is a Deoxyribonucleic Acid?
They are more commonly known as DNA. They form the inherited genetic material inside each human cells. In humans, each gene is a segment of a DNA molecule. When a cell divides, its hereditary information passes onto the next generation of cells.
94
What is a Ribonucleic Acid?
More commonly known as RNA. They relay instruction from the genes to guide each cells synthesizes of proteins from amino acids.
95
What are the three parts that nucleotides consists of?
Nitrogen base- contains four bases.
Pentose sugars - a five carbon sugar called deoxyribose attaches to each base in DNA.
Phosphate group - phosphate groups alternate with pentose sugars to form the 'backbone' of a DNA strand.
96
What are the four nitrogen bases? Name which are purines and which are pyrimidines
Adenine and Guanine - the purines
Thymine and Cytosine - the pyrimidines
97
In a double helix model, what are the paired bases and what is it held together by?
Adenine pairs with thymine
Cytosine pairs with guanine
They are held together by hydrogen bonds.
98
How do mutations occur in DNA?
Any changes that occurs in the base sequence of a dNA strand is called a mutation. Some mutations can cause a cells death, cancer, or genetic defect.
99
What are the three different types of RNA?
Messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).
100
What is Adenosine triphosphate?
msot commonly known as ATP. ATP is the 'energy currency' of living system.s ATP transfers the energy from exergonic catabolic reactions to power cellular activities that require energy.
101
What are ATPhase and Adenosine diphosphate (ADP)?
When water is added to ATP, the 3rd phosphate group is removed. The reaction liberates energy. The enzyme that catalyzes the hydrolysis of ATP is called ATPhase.
The removal of the 3rd phosphate group produces a molecule called Adenosine diphosphate.
102
Explain the process of Cellular respiration. What are its two phases?
The energy needed to attach a phosphate group to ADP is supplied mainly by the catabolism of glucose in a process called cellular respiration.
The anaerobic phase - Absent oxygen. Releases two molecules of ATP. Glucose not completely broken down. Occurs in cytoplasm.
Anaerobic phase - With oxygen. Releases three or thirty two ATP. Glucose completely broken down. Occurs in the mitochondria.
103
Define cells. What is the study of cells called?
Cells are the basic, living, structural, and functional units of the body. The study of cells is called cell biology or cytology.
104
What are the three main parts of a cell?
Plasma membrane, cytoplasm, and nucleus.
105
Define Plasma membrane.
Forms the cells flexible outer surface, separating the cells internal environment from the external environment. It is a selective barrier that regulates the flow of materials into and out of the cell. It also plays. a key role in communicating among cells, between cells and their external environment.
106
Define Cytoplasm. What are its two compartments?
Consists of all the cellular contents between the plasma membrane and the nucleus.
It has two compartments; cytosol, which is the fluid portion, also called intracellular fluid. Within the cytosol there are the organelles which are little organs in the cell.
107
Define The nucleus. What is the main component in the nucleus?
The nucleus is a large organelle that houses most of a cells DNA. In the nucleus, each chromosome contains thousands of hereditary units called genes that control most aspects of cellular structure and function.
108
Describe the Fluid mosaic model.
This model states the molecular arrangement of the plasma membrane resembles. a continually moving sea of fluids lipids that contains a mosaic of different proteins.
109
Describe what the lipid bilayer is. What are the three types of lipid molecules in it?
The basic structural framework of the plasma membrane. Two back to back layers made up of three types of lipid molecules - Phospholipids, cholesterol, and glycolipids.
110
How are the phospholipids arranges in the bilayer? What is facing what?
The phospholipid is arranged for the 'head' to be facing outward towards the water, loves the water. The 'tail' is facing inward, facing each other. They hate the water.
111
Differentiate between integral and peripheral proteins.
Membrane proteins are classified as integral or peripheral.
Integral proteins extend into or through the lipid bilayer and are firmly embedded into it.
Peripheral proteins are not firmly embedded in the membrane.
112
What are the functions membrane proteins?
-Some integral proteins form ion channels.
-Integral proteins acts as carriers/
-Integral proteins called receptors.
-Some integral proteins are enzymes that catalyze specific chemical reactions.
-Integral proteins may also serve as inkers which anchors filaments.
113
Define concentration gradient.
A difference in the concentration of a chemical from one place to another (inside vs. outside of the membrane). Typically, the inner surface of the plasma membrane is more negatively charged and the outer surface is more positively charged.
114
What is an electrical gradient?
The electric potential that acts on an ion to drive the movement of the ion in one or another direction.
115
Define a membrane potention.
The difference in charge between the inside and outside of a cell.
116
Define a electrochemical gradient.
Concentration and electrical gradaint help more substances across the plasma membrane. The combined influence of the concentration gradient and the electrical gradient on movement of particular ion.
117
Differentiate between passive and active process.
Passive process - substances moves down its concentration or electrical gradient to cross the membrane using gradient to cross the membrane using only its own kinetic energy.
Active process - cellular energy is used to drive the substances uphill against its concentration or electrical gradient.
118
Define diffusion.
A passive process in which the random mixing of particles in a solution. Occurs due to particles of kinetic energy.
119
What are the five factors that influence the diffusion rate?
-Steepness of the concentration gradient.
-Temperature
-Mass of the diffusing substance.
-Surface rate
-Diffusion distance.
120
What are the three types of diffusion?
Simple diffusion, facilitated diffusion and osmosis.
121
Define simple diffusion.
A passive process in which substances move freely through the lipid bilayer of the plasma membranes of the cells without the help of transport proteins.
122
Define Facilitated diffusion.
Solutes that are too polar or highly charged cross the plasma membrane by a passive process called facilitated diffusion. An integral membrane protein (membrane channel or a carrier) assists substances across the membrane.
123
Differentiate between channel mediated facilitated diffusion and carrier mediated facilitated diffusion.
In channel medicated facilitated diffusion, a solute moves down it s concentration gradient across the lipid bilayer through a membrane channel. In carrier mediated facilitated diffusion, a carrier or transporter moves a solute down its concentration gradient in a plasma membrane. Once all the carriers are occupied, the transport maximum is reached.
124
Define Osmosis.
Is unassisted diffusion of water. Water crosses the plasma membranes from an area of higher water concentration to an area of lower concentration.
125
How does water pass through during osmosis?
1). By moving between neighbouring phospholipids molecules in the lipid bilayer via simple diffusion.
2). By moving through aquaporins also known as water channels, they control the water contents of cells.
126
Differentiate hydrostatic vs. osmosis pressures.
Hydrostatic pressure is water being pushed out of blood vessels with too much water. Causing edema. Equilibrium is reached when just as many water molecules move from right to left.
Osmotic pressure is if there is too many water molecules in the plasma, water will be pulled into the vessels. Causing higher blood pressure.
127
Define tonicity.
The ability of a solution surrounding a cell to cause that cell to gain or lose water.
128
What is the difference between Isotonic, hypertonic, and Hypotonic solutions?
Any solutions in which the cells maintain its normal shape and volume is an isotonic solutions. The concentrations of solutes that cannot cross the plasma membrane are the same on both sides of the membrane.
HYPOtonic solution has a lower concentration of solutes than the cytosol. Water molecules enters the cell faster than they leave, causing it to swell and bursts. The rupture of RBCs in this manner is called hemolysis. Pure water is very hypotonic.
HYPERtonic has a higher concentration of solutes than does the cytosol. Water molecules move out of the cells faster than they enter, causing the cells to shrink. The shrinking of cells is called crenation.
129
What is active transport?
Active transport is considered an active process because energy is required for carrier proteins to move solutes across the membrane against a concentration gradient.
130
What is primary active transport?
Energy derives from hydrolysis of ATP, changes the shape of a carrier protein. Carrier proteins that mediate primary active transport are often called pump.
131
How does a sodium-potassium pump work?
The most prevalent primary active transport mechanism expels sodium ions and brings in potassium ions. Two potassium ions for every three sodium ions out.
132
What is secondary active transport?
Uses energy stored in the concentration gradient of ions. In secondary active transport, a carrier protein simultaneously binds to sodium ions and another substances and then changes its shape so both substances cross the membrane at the same time.
133
Differentiate between symporters and antiporters.
Symporters move two substances in the same direction. Antiporters move two substances in opposite directions across the membrane.
134
Define transport vessicles.
A vesicle is a small, spheric sacs. A variety of substances are transported in vesicles from one structure to another within cells.
135
Differentiate between endocytosis and exocytosis.
Endocytosis - materials move into the cells.
Exocytosis - materials move out of the cells.
136
Define Receptor mediated endocytosis.
A highly selective type of endocytosis by which cells take up specific ligands. A vesicle forms after a receptor protein in the plasma membrane recognizes and binds to a particular particle in the extracellular fluid.
137
Define Phagocytosis. What are the two types?
Meaning cell eating. A form of endocytosis in which the cells engulfs large solid particles such as worn out cells, whole bacteria or viruses. Takes in large particles.
There are two main types;
Macrophages - located in many body tissues
Neutrophils - A type of WBC
138
Define Bulk phase endocytosis.
Meaning cell drinking. A form of endocytosis in which tiny droplets of extracellular fluids are taken up. The plasma membrane folds inwards and forms a vesicle containing a droplet of extracellular fluid. Takes in molecules (small particles).
139
How does exocytosis work?
Exocytosis releases materials from a cell. All cells carry out exocytosis especially;
1). Secretory cells
2). Nerve cells
During exocytosis, waste could also be expelled.
140
Define Transcytosis.
An active process. Vesicles undergo endocytosis on one side of a cell, move across the cell, and then undergo exocytosis on the opposite side.
Vesicular transport of macromolecules form one side of a cell to the other.
141
What is cytoplasm? and what is a cytosol?
Cytoplasm consists of all cell contents between the plasma membrane and the nucleus. Cytosol is the intercellular fluid. The fluid portion of the cytoplasm that surrounds the organelles. The cytosol is the site of many chemical reactions required for a cells existence.
142
What are the three structures that make up the cytoskeleton?
Microfilaments - the thinnest elements of the cytoskeleton. Consists of a proteins actin and myosin. Has two general functions; they help generate movement and provide mechanical support. They are involved in muscle contraction, cell division, and cell locomotion.
Intermediate filaments - they help stabilize the position of organelles and help attach cells to another.
Microtubules - composed mainly of the protein tubulin. They also help determine cell shape. They also function in the movement of organelles.
143
Define organelles.
Specialized structures in a cell and performs specific functions in cellular growth, maintenance, and reproduction. Each organelles has its own set of enzymes and serves as a functional compartment and specific biochemical processes.
144
What are centrosomes?
Located near the nucleus. Also called microtubule organelles centre. Has two components; centrioles and pericentriolar matrix. The two centrioles composed each with nine clusters of three microtubules arranged in a circular pattern. Surrounding the centrioles is the pericentriolar matrix. This contains hundreds of ring shaped complexes composed of the protein tubulin.
145
Differentiate between cilia and flagelle.
Cilia are numerous short, hair like projections that extends form the surface of the cell. Cilia moves fluids along a cells surface.
Flagella are longer than ilia. They usually move an entire cell. Sperm cells are the only cells that have these.
146
Define ribosomes?
The site of protein synthesis. Each ribosome contains more than 50 proteins. Ribosomes that are attached to the surface of the nuclear membrane. Synthesize proteins destined for other organelles, for insertion in the plasma membranes, or for export from the cell.
147
Define endoplasmic reticular. What are smooth ER and rough ER?
Endoplasmic reticulum is a network of membranes in the form of flattened sacs or tubules. Cells contains two distinct forms of ER.
Rough ER is continuos. The outer surface of rough ER is studded with ribosomes. Rough ER produces secretory proteins, membranes, and many other organelle proteins.
Smooth ER extends from the rough ER. Smooth ER does not have ribosomes but instead contains unique enzymes that make it functionally more diverse than rough ER. Smooth ER does not synthesize protein, but instead synthesizes fatty acids and steroids.
148
Define golgi complex.
It consists of five to twenty cisterns. The golgi complex modifies, sorts, packages, and transports proteins. Proteins goes through the golgi complex through maturation of the cisternae and exchange.
149
What are lysosomes?
From the golgi complex. They contain powerful digestive and hydrolytic enzymes that can breakdown a wide variety of molecules once lysosomes fuse with vesicles formed during endocytosis. Lysosomal enzymes also he lprecycle worn out cell structures.
150
Define mitochondria.
The powerhouses of the cell, they generate the most ATP. Located within the cells where oxygen enters the cell or where ATP is used. The internal membrane are a series of folds called mitochondrial cristae. The central fluid filled cavity is enclosed by the internal membrane called mitohcondria matrix.
Mitochondrial genes are only inherited from the mom.
151
What is a nucleus? What separates the nucleus from the cytoplasm?
A spherical or oval shaped structure that usually is the most prominent feature of a cell. Most have a singular nucleus, some have none and some have multiple.
A double membrane called the nucleus envelope separated the nucleus form the cytoplasm.
152
What is the function of nuclear pores?
Nuclear pores control the movements of substances between the nucleus and cytoplasm.
153
What is inside a nucleus?
Inside the nucleus are one or more spherical bodies called nucleoli that functions in producing ribosome.
Inside the nucleus are most of the cells hereditary units called genes, which controls cellular structure and direct cellular activities.
154
How many chromosomes does a human cell have?
There are 46 chromosomes in each cell.
155
What are proteome?
Refers to all of an organisms proteins.
156
What is transcription in RNA?
The process in which a genes DNA sequence is copied to make an RNA strands.
Three types of RNA are made from this process
-Messenger RNA
-Ribosomal RNA
-Transfer RNA
157
Differentiate between the three types of RNA.
Messenger RNA - (mRNA) carries the genetic information needed to make proteins.
Ribosomal RNA (rRNA) joins the ribosomal proteins to make ribosomes
Transfer RNA - (tRNA) carries amino acids to the ribosomes during protein synthesis.
158
What does the RNA polymerase do?
It catalyzes transcription of DNA.
159
In transcription, what is the base pairs and their complimentary?
Cytosine ---> Gunine
Thymine ---> Adenine
160
What is translation in RNA?
The nucleotide sequence in an mRNA molecule specifies the amino acids sequence of a protein.
161
Define cell division.
The process by which cells reproduce themselves. There are two types; somatic cell division and reproductive cell division.
162
Differentiate between somatic cell and germ cell.
Somatic cells is any cells in the body other than a germ cell.
Germ cells are gametes (sperm or oocytes) or any precursor cell destined to become a gamete.
163
What division does somatic cells undergo?
Mitosis and cytokinesis. To produce two genetically identical cells. Somatic cells replaces dead or injured cells.
164
What division does reproductive cell division undergo?
Meiosis. Produces gametes, which are the cells needed to form the next generation of sexually reproducing organism.
165
What are the four stages of mitosis?
- Prophase
- Metaphase
- Anaphase
- Telophase
166
What are the three 'destinies' of a cell?
1). To remain alive and function without dividing.
2). To grow and divide.
3). Die.
167
Differentiate between apoptosis and necrosis.
Apoptosis is a normal type of cell death. Necrosis is a pathological type of cell death that results from tissue injury.
168
Define Meiosis and when it occurs.
Meiosis is the reproductive cell division that occurs in the gonads, produces gametes in which the number of chromosomes is reduces in half.
169
Differentiate between Haploid and Diploid.
Gametes contain a single cell of 23 chromosomes making it a haploid cell, once its fertilized, it restores to the diploid number.
Somatic cells contain two sets of chromosomes, due to this they are called diploid cells.
170
What are the two stages of meiosis?
Meiosis one and meiosis two.
171
Define tissue.
Tissue is a group of cells that usually have a common origin in an embryo and function together to carry out specialized activities.
172
Differentiate between histology and pathologist.
Histology is the study of tissue.
Pathologist examines cells and tissues to help with accurate diagnosis.
173
What are the four basic body tissue?
- Epithelial tissues
- Connective tissues
- Muscular tissues
-Nervous tissues
174
Define epithelial tissues.
Covers body surfaces and lines hollow organs, body cavities, and ducts, also glands. It allows the body to intersect with both its internal and external environment.
175
Define connective tissue.
Protects and supports the body and its organs. Various types binds organs together, stores fat as reserves, and helps the body with immunity to disease causing organisms.
176
Define muscular tissues.
Composed of cells specialized for contraction and generation of force. It also generates heat to warm the body.
177
Define nervous tissues.
Detects changes inside and outside of the body and responds visa signals called action potential.
178
Define cell junctions.
Contact points between the plasma membrane of tissue cells.
179
What are the five types of cell junctions?
- Tight junction
- Adherence junction
- Desmosomes
- Hemidesmosomes
- Gap junction
180
Define tight junction.
Consists of weblike proteins that fuse together the outer surfaces of adjacent plasma membranes to seal off passageways between adjacent cells. They prevent the contents of organs from leaking into the blood or surrounding tissues.
181
Define adherence junction.
Contains plaque, a dense layer of proteins on the inside of the plasma membrane that attaches both to membrane proteins and to microfilaments of the cytoskeleton.
182
Define desmosomes.
Also contains plaque and have transmembrane glycoproteins that extends into the intercellular space between adjacent cells membranes and attach cells to one another.
Plaque of desmosomes does not adhere to microfilaments, but attaches to intermediate filaments.
Desmosomes are common among cardiac muscle and cells that make up the epidermis.
183
Define hemidesmosomes.
Resembles desmosomes but they do not link adjacent cells. The transmembrane glycoproteins in hemidesmosomes are integrins.
Integrins attach to intermediate filaments made of the protein keratin.
On the outside, the integrins attach to the protein laminin. Hemidesmosome anchors cells to the basement membrane.
184
Define gap junctions.
Membrane proteins called connexins form tiny fluid filled tunnels called connexons. Separated by intercellular space. Through the connexons, ions and small molecules can diffuse, but larger molecules can not.
Gap junctions allows the cells in a tissue to communicate with one another. They also enable nerve or muscle impulses to spread rapidly among cells.
185
Differentiate between epithelial tissue and connective tissue.
- In epithelial tissue, the cells are tightly packed together. In connective tissue, a large amount of matrix separates cells.
- Epithelial cell has no blood vessels, but most connective tissues have significant networks of blood vessels.
-Epithelial tissue almost always forms surface layers and is not covered by another tissue. Except for when epithelial lining of blood vessels where blood constantly passes over the epithelium.
186
Define epithelial tissue and its functions.
Also called epithelium, consists of cells arranged in continuous sheets, in either single or multiple layers.
Epithelial tissues protect, secretes, absorbs, and excretes.
Epithelial tissue has its own nerve supply, but is avascular meaning it is without vessels.
187
What are the two ways epithelial tissue is arranged?
1). Covering and lining various surfaces
2). Forming the secreting portions of glands
188
What are the three various surfaces of covering and lining epithelial cells?
Apical surface - (free surface) faces the body surface, a body cavity. The interior space of an internal organs, or a tubular ducts that receives cell secretions.
Lateral surface - faces the adjacent cells on either side, may contain tight junctions, adheres junctions, desmosomes and/or gap junctions.
Basal surface - Opposite the apical surface. The deepest layer of epithelial cells adhere to extracellular membrane like the basements membrane.
189
Define basement layer.
A thin extracellular layer that commonly consists of two layers, the basal lamina and reticular lamina.
190
Differentiate between basal lamina and reticular lamina.
Basal lamina - Is closer to (and secreted by) the epithelial cells. It contains proteins such as laminin and collagen, glycoproteins, and proteoglycans.
Reticular lamina - Closer to the underlying connective tissue and contains proteins such as collagen produces by fibroblasts.
191
Explain how epithelial cells are versatile and flexible?
Epithelial tissues is repeatedly subjected to physical stress and injury. A high rate of cell division allows epithelial tissue to constantly renew and repair.
192
What are the two classifications of epithelial tissue?
- Arrangements of cells in layers
- Cell shapes
193
Define the three arrangements of cells.
Simple epithelium - a single layer of cells that functions in diffusion, osmosis, filtration, secretion, and absorption.
Pseudo-stratified epithelium - appears to have multiple layers of cells because the cell nuclei lie at different levels.
Stratified epithelium - consists of two or more layers of cells that protects underlying tissues in the locations where there is considerable wear and tear.
194
What are the four possible shapes of a cell?
Squamous cells - are thin, allows for the rapid passage of substances.
Cuboidal cells - they are tall as they are wide. They function in either secretion or absorption.
Column cells - much taller than they are wide. They protect underlying tissues, and are specialized for secretion and absorption.
Transitional cells - changes shape, organs such as the urinary bladder stretch to a larger size and then collapse to a smaller size.
195
Define gland and glandular epithelium.
Their function is secretion, accomplished by glandular cells. A gland consists of epithelium that secretes substances into ducts, onto a surface, or eventually into the blood.
196
Differentiate between endocrine glands and exocrine glands.
- Endocrine glands called hormones, enters the interstitial and then diffuse into the blood stream without flowing through ducts. Endocrine secretion have far reaching effects because they are distributed by the bloodstream.
- Exocrine glands secretes their products into ducts that empty onto the surface of a covering and lining epithelium. Exocrine glands have limited effects and some maybe harmful if they entered the blood stream.
197
How are exocrine glands categorize?
1). Whether their ducts are branched or unbranched.
2). the shape of the secretory portions of the glands.
198
What are the four categories of exocrine glands?
Simple glands - does not branch
Compound glands - branches
Tubular glands - tubular secretory parts
Acinar glands (alveolar glands) - rounded secretory parts
Tubuloracinar glands - have both tubular and more rounded secretory parts.
199
What are three different types of exocrine glands?
Merocrine gland - are synthesized on ribosomes attached to rough ER. Processes, stored and packaged by the golgi complex and then released from the cell in secretory vesicles via exocytosis.
Apocrine glands - accumulate their secretory product at the apical surface of the secretory cell. Then that portion of the cell pinches off by exocytosis from the rest of the cells to release the secretion.
Holocrine glands - accumulates as a secretory product in their cytosol. As the secretory cell matures, it ruptures and becomes the secretory products. Due to it rupturing, cell division takes place to replace cells.
200
Define connective tissue and its functions.
One of the most abundant and widely distributed tissues in the body. Connective tissue binds together, supports and strengthens either body tissues.
It also protects and insulates internal organs, as well as compartmentalize structures such as skeletal muscles.
Connective tissue is highly vascular.
201
What are the two basic elements of connective tissues?
Extracellular matrix and cells.
202
Define extracellular matrix.
It is the material located between its widely spaced cells. It's matrix consists of protein fiber and ground substances. It provides support, it surrounds cells, it also gives structure to cells and tissue in the body.
203
What are the six types of connective tissue?
- Fibroblasts
- Macrophages
- Plasma cells
- Mast cells
- Adipocytes
-Leukocytes
204
Define fibroblasts.
Large, flat cells with branching process. They are present in all general connective tissue, and usually are the most numerous.
205
Define macrophages.
They are phagocytes that develop from monocytes. Fixed macrophages resides in a particular tissue. Wandering macrophages have the ability to move throughout the tissue and gather at sites of infection or inflammation to carry on phagocytosis.
206
Define plasma cells.
Also called plasmacytes. Found in many places in the body, but most plasma cells reside in connective tissue, especially the gastrointestinal and respiratory tract.
207
Define mast cells.
Involved in the inflammatory response and can also bind to, ingest, and kill bacteria. Also called mastocytes.
208
Define adipocytes.
Fat cells or adipose cells. Connective tissue cells that store fat. They are found in the skin and around organs such as the heart and kidneys.
209
Define Leukocytes.
Not found in significant numbers in normal connective tissue. In certain conditions, they migrate from blood to connective tissue. Neutrophils gather at sites of infection .
210
What are the two extracellular matrix major components?
- Ground substances
- Fibers
211
Define ground substance.
The component of a connective tissue between the cells and fibers. It supports cells, binds them together, stores water, and provide medium for exchange between blood and cells.
212
Define fibers in connection to extracellular matrix.
They function to strengthen and support connective tissue. There are three types;
- Collagen fibers
- Elastic fibers
- Reticular shape
213
Define Hyaluronic acid.
A viscous, slippery substances that bind together cells, lubricates joints, and help maintain the shape of the eyeballs.
214
Define collagen fibers.
Very strong and resists pulling or stretching, but not stiff and its very flexible. Collagen fibers often occur in parallel bundles, this arrangement adds great tensile strength to the tissue. Collagen fibers contain collagen which is the most abundant protein in the body.
215
Define elastic fibers.
Branches and joins together to form a fibrous network within a connective tissue. It consists of the protein elastin and surrounded by a glycoprotein named fribillin. It could stretch up to 150% of their relaxed length without breaking, and they also have the ability to return to their original shape.
216
Define reticular shape.
Consisting of collagen arranged in fine bundles with a coating of glycoproteins. They provide support in the walls of blood vessels and forma network around the cells in some tissues. They are produces by fibroblasts. They also provide support and strength. Reticular fibers also help form the basement membrane.
217
What are the two supporting connective tissue?
- Cartilage
- Bone tissue
218
Define cartilage.
Dense network of collagen fibers and elastic fibers firmly embedded in chondroitin sulfate (component of ground substances). Cartilage resilience is due to its chondroitin sulfate.
Cartilage does not have a blood supply; instead, it secrete antiangiogenesis factor which is a substance that prevents blood vessel growth.
Mature cartilage is called chondrocytes. It occurs singly or in groups within spaces called lacunae.
219
What are the three types of cartilage?
- Hyaline cartilage
- Fibrocartilage
- Elastic cartilage.
220
What are the two basic patterns of cartilage crowth?
Interstitial growth - there is growth within the tissue. This growth pattern occurs while the cartilage is young and pliable, during childbirth and adolescence.
Appositional growth - there is growth at the outer surface of the tissue. Extracellular matrix accumulates beneath the perichondrium on the outer surface of the cartilage, causing it to grow in width. Appositional growth starts later and continues through adolescence.
221
Define bone tissue.
Cartilage, joints, and bones make up the skeletal system. It supports soft tissues, protects delicate structures and works with skeletal muscles to generate movements. Bones store calcium and phosphorus, it also houses red and yellow bone marrow.
222
What are the two classification of bone tissue?
- Compact bone
- Spongy bone
223
What is the basic unit of compact bone? and what are its four parts?
The basic unit of compact bone is an osteon or haversian system.
- Lamellae
- Lacunae
- Canaliculi
- Central canal
224
Define lamallae.
It gives bone its hardness and compressive strength, and collagen fibers which gives bone its tensile strength. They are concentric rings of extracellular matrix. The lamellae are responsible for the compact nature of this type of bone tissue.
225
Define lacunae.
Small spaces between lamellae that contains mature bone cells called osteocytes.
226
Define canaliculi.
Projecting from the lacunae are the canaliculi. Which are networks of minute canals containing the processes of osteocytes. It also provides routes for nutrients to each osteocytes and for waste to leave them.
227
What is in the central canal?
It contains blood vessels and nerves.
228
What is the main difference between compact bone and spongy bone?
Spongy bones lacks osteons. Instead they contains columns of bone called trabeculae. Which contains lamellae, osteocytes, lacunae, and canaliculi.
The spaces between trabeculae are filled with red bone marrow. Spongy bone is mainly for bone cell productions.
229
What is liquid connective tissue? And what is the two types?
Has liquid as its extracellular matrix.
- Blood tissue
- Lymph
230
Define blood tissue. And its different types.
Blood has a liquid extracellular matrix called blood plasma and formed element.
Blood plasma - pale yellow fluid that consists mostly of water.
Red blood cells - transports oxygen to body cells and remove some CO2.
White blood cells - involved in phagocytosis, immunity, and allergic reactions.
Platelets - participates in blood clotting.
231
Define lymph.
The extracellular fluid that flows in lymphatic vessels. Contains less protein than blood plasma.
232
Define membrane.
Membranes are flat sheets of pliable that cover or line a part of the body. The majority consists of epithelial layer and a connective tissue called epithelial membrane.
233
Define synovial joints.
A type of membrane that lines joints and contains connective tissue but not epithelium.
234
Name the three epithelial membrane.
- Mucous membranes
- Serous membrane
- Cutaneous membrane
235
Define mucous membranes.
Lines the body cavity that opens directly to the exterior. The underlying connective tissue of the mucous membrane is called lamina proper. The lamina proper allows some flexibility of the membrane and offers some protection. Oxygen and nutrients diffuse from the lamina proper to the covering epithelium.
236
Define serous membranes.
Lines a body cavity that does not open directly to the exterior, and it covers the organs that are within the cavity. Serous membrane is covered by mesothelium. Parietal layer attaches to the cavity wall. Visceral layer covers and adheres to the organs in a cavity. The mesothelium secretes serous fluid, which allows the organs to glide easily over one another.
237
Define cutaneous membranes.
(Skin) Covers the entire surface of the body and consists of a superficial portion called epidermis and a deeper portion called the dermis.
238
Define synovial membrane.
Lines the cavities of freely movable joints. It also lines structures that do not open to the exterior. Synovial membrane are composed of a discontinuous layer of cells called synoviocytes. Which secretes some of the components of synovial fluids. The fluid lubricates and nourishes the cartilage covering the bones at moveable joints and contains macrophages.
239
Define muscular tissue and what it consists of.
It consists of elongated cells called muscle fibers or myocytes that can use ATP to generate force. Muscular tissue produces body movements, maintains posture, and generates heat.
240
Name the three muscular tissue types.
- Skeletal muscle tissue
- Cardiac muscle tissue
- Smooth muscle tissue
241
Define skeletal muscle tissue.
Skeletal muscle tissue consists of long, cylindrical, striated fibers. It is considered voluntary because it can be made to contract or relax by conscious control. It is usually attached to bones by tendons and its function is motion, posture, heat production, and protection.
242
Define cardiac muscle tissue.
Consists of branched, striated fibers with usually only one nuclei, sometimes two. Attach end to end by transverse thickenings of plasma membrane called intercalated disks. These disks contain desmosomes and gap junctions. It is considered an involuntary muscle.
Cardiac tissue is located in the heart wall. And its function is to pump blood to all parts of the body.
243
Define smooth muscle tissue.
Consists of non striated fibers, but instead, a small spindle shaped cell thickest in the middle an contains a single, centrally located nucleus.
Usually involuntary; can produce powerful contraction.
Its function is motion.
244
What are the two principal types of nervous tissue?
- Neurons
- Neuroglia
245
Define neurons.
Also called nerve cells, are sensitive to various stimuli. They convert stimuli into electrical signals called nerve action potential and conducts it to other neurons, muscle tissue or to glands.
246
What are the three basic parts of a neuron?
Cell body - contains the nucleus
Dendrites - they are the major receiving or input portion of a neuron
Axon - it is the output portion of a neuron, conducting nerve impulses towards other neuron or to some other tissue.
247
Define neuroglia.
They do no conduct nerve impulse but instead have a more supportive functions.
248
Define excitable cells.
Neurons and muscle fibers are considered excitable cells because they exhibit electrical excitability, which is the ability to respond to certain stimuli by producing electrical signals. such as action potential. When an action potential forms in a neuron, the neuron releases chemicals called neurotransmitters.
249
What is the integumentary system consists of?
Skin, hair, oil and sweat glands, nails, and sensory receptors.
250
What do dermatologists do?
Medical specialists that deals with the structure, function, and disorders of the integumentary system.
251
What is the largest organ in the body?
The skin.
252
Name the two parts of skin.
- Epidermis
- Dermis
253
What is under the dermis but is not part of the skin? What is its function?
Subcutaneous layer. It serves as a storage deposit for fat and contains large blood vessels that supply the skin. This portion also contains nerve endings called lamellated corpuscles that are sensitive to pressure.
254
Define epidermis.
Epidermis is avascular. It's composed of keratinized stratified squamous epithelium.
255
What are the four principles type of cells in epidermis?
Keratinocytes - produces the protein keratin.
Melanocytes - Develops from the ectoderm of a developing embryo and produces the pigment melanin.
Intraepidermal macrophages - also called langhans cells. They arise from ted bone marrow and migrate to the epidermis. They participate in immune responses. Easily damaged by UV light.
Tactile epithelial cells - also called markel cells. The least numerous of the epidermal cells, also the deepest. Tactile epithelial cells and tactile discs detect touch sensations.
256
Define keratin.
Keratin helps protect the skin and underlying tissues from abrasion, heat, microbes, and chemicals.
257
Define lamellar granules.
Produced by keratinocytes. They decrease water entry and loss and inhibits foreign material from entering.
258
Define melanin.
A yellow - red, or black - brown pigment that contributes to the skin colour and absorbs UV light.
259
Define stratum basale.
The deepest layer of the epidermis. some cells in this layer are stem cells to continually produce new keratinocytes. Stratum basale contains melanocytes. They are closest to blood vessels and receive the most nutrients and oxygen.
260
Define stratum spinosum.
Above the basale. The keratinocytes in the spinosum, which are produces by the stem cells in the basal layer. The keratinocytes of this layer produces coarser bundles of keratin. The cells are connected by desmosomes, which are tightly joint to one another.
261
Define stratum granulosum.
The layer of keratinocytes are undergoing apoptosis. The cell begins to degenerate the farther they move from the dermis. The nucleus eventually breaks down and the cells die.
Stratum granulosum essentially functions as a waterproof barrier, to keep water out and prevents water from coming out.
262
Define stratum lucidum.
Present only in the thick skin of areas such as the fingertips, palms, and soles. It contains dead keratinocytes that contain large amounts of keratin and thickened plasma membranes.
263
Define stratum corneum.
Consists of flattened dead keratinocytes. These cells no longer contain a nucleus or any organelles. Cells here are continuously shed. Increased cell production results in the formation of callus.
264
Define the process of keratinization.
As the newly formed cells from the stratum basale are slowly pushed up, they accumulate more and more keratin, a process called keratinization. Then they undergo apoptosis.
265
What is the second deepest part of the skin?
The dermis.
266
Define the dermis.
The dermis is composed of dense irregular connective tissue containing collagen and elastic fibers. The dermis also has the ability to stretch and recoil as well as resists pulling and stretching. Blood vessels, nerves, glands, and hair follicles are embedded in the dermal layer. The dermis is essential to the survival of the epidermis.
267
What are the two division of the dermis?
- Superficial papillary region
- Deeper reticular region
268
Define papillary region.
It contains thin collagen and fine elastic fibers. Its surface area is greatly increased by dermal papillae. Dermal papillae contains capillary loop (blood vessels). Some contain tactile receptors called corpuscles of touch which are nerve endings sensitive to touch.
269
Define Reticular region.
Attached to the subcutaneous layer, contains bundles o thick collagen fibers, scattered fibroblasts, and various wandering cells. While the papillary supplies nutrition to the epidermis, the reticular layer provides strength and flexibility.
270
What are your fingerprints called?
Epidermal ridges.
271
What are the three pigments that impact the colour of the skin?
Melanin, hemoglobin, and carotine.
272
Name the three accessory structures of the skin.
Hair, skin glands, and nails.
273
What is the functions of the hair?
Also called pili. Hair in the head protects the scalp from injury and the suns rays. Also decreases the heat loss from the scalp.
Eye brows and lashes protects the eye from foreign objects.
274
Name the two portions of a hair.
- Hair shaft
- Hair root
275
What are the three concentric layers of the hair cells?
- Medulla
- Cortex
- Cuticle of the hair
276
I hope you trusts the seeds that your are planting.
277
Name the five types of skin glands.
- Sebaceous glands
- Sudoriferoug glands
- Eccrine sweat glands
- Apocrine sweat glands
- Ceruminous glands
278
Define sebaceous gland.
Also called oil glands, are simple acinar (rounded) glands. Usually opens at the neck of a hair follicle. Absent in the palms and soles. These glans secretes an oily substance called sebum. Sebum helps keep hair from drying and prevents excessive evaporation of water from skin and inhibits bacterial growth.
279
Define sudoriferous glands.
Also called sweat glands. These glands release sweat. It opens into the hair follicle or onto the skin surface through pores.
280
What are the two types of sudoriferous glands?
- Eccrine glands
- Apocrine glands.
281
Define eccrine sweat glands.
Coiled tubular glands that are more common than apocrine glands. The main function is to help regulate body temperatures through evaporation.
Eccrine sweat glands open directly onto the skins surface.
Occurs soon after birth.
282
Define thermoregulation.
The regulation of temperature.
283
Differentiate between insensible perspiration and sensible persperation.
Insensible perspiration is interstitial fluid loos by evaporation.
Sensible perspiration is water excreted by sweat glands.
284
Define apocrine sweat glands.
Also called tubular glands but have larger ducts. Their secretion is via exocytosis.
Does not occur until puberty.
Does not play a part in thermoregulation.
Apocrine glands open onto the hair follicles.
The cause of body odours.
285
Define serumenous glands.
Modified sweat glands in the external ear. These glands produce a waxy lubricating secretion. Their ducts open either directly onto the surface of the external auditory canal or into the ducts of sebaceous gland. Combination of seruminous and sebaceous gland is called cerumen, or earwax.
286
What is nails made out of?
Plates of tightly packed, hard, and dead keratinized epidermal cells.
287
What are the three structures of a nail?
- Nail body
- Free body
- Nail root
288
What are the three functions of nail?
1). They protect the distal end of the digit.
2). They provide support and counter pressure to the palmar surface of the fingers to enhance touch perception and manipulation.
3). They allow us to grasp and manipulate small objects, and they can be used to scratch and groom the body.
289
What are the six functions of the skin?
- Thermoregulation
- Blood reservoir
- Protection
- Cutaneous sensations
- Excretion and absorption
- Synthesis of Vitamin D
