Anatomy test 1
I. 2 BRANCHES OF SCIENCE DEALING WITH THE HUMAN BODY
A. Anatomy-the study of the structure and organization of the body and the study of
relationships of body parts to one another.
1. Specifically, anatomy deals with body forms and structures and how these structures
are arranged.
2. Subdivisions of Anatomy:
a. Gross Anatomy
b. Microanatomy (Histology)
B. Physiology-the study of the function of the human body and its parts.
C. The Principle of Complementary of Structure and Function-states that function of body parts
in the human body always reflects structure.
II. LEVELS OF STRUCTURAL ORGANIZATION IN THE HUMAN BODY
A. The Chemical Level-lowest level of organization; this includes atoms (carbon, oxygen etc..)
and molecules (water, DNA).
B. The Cellular Level-includes cells which are the smallest living units of matter.
1. There are many different types of cells in the human body. Each type of cell has a
different structure and performs a different function. Cells contain special organelles
(mini organs) that carry out many of the essential functions for the cell.
C. The Tissue Level
1. Tissues-groups of cells that work together to carry out similar functions. There are a
variety of different tissues in the human body.
D. The Organ Level
1. Organs-structures that are composed of 2 or more tissues that work together to
perform similar functions.
E. The System Level
1. Systems-groups of organs that work together to carry out similar functions.
2. What are the 11 major systems in the human body? Integumentary, skeletal, muscular, respiratory, cardiovascular, lymphoid, urinary, endocrine, nervous, digestive, and reproductive systems
3. List at least one organ in each system.
F. The Organismic Level-the highest level of organization in the human body.
1. Organism-a living individual.
III. ANATOMICAL POSITION-in this position, the subject stands upright, facing the observer with feet
flat on the floor, arms placed at the sides and palms of the hands turned forward.
A. This position provides a standard method for observing the various structures associated with
the human body.
B. The body is organized into two major portions:
1. The Axial Portion
2. The Appendicular Portion
C. Tables 1.2 and1.3-know the major regions of the axial and appendicular portions of the body
from these two tables.
IV. DIRECTIONAL TERMS-are used to locate various structures in the human body.
A. Know the major Directional Terms from Table 1.1 of the textbook. Be able to use the terms
correctly.
V. PLANES AND SECTIONS OF THE HUMAN BODY
A. Planes are imaginary flat surfaces that divide the body into sections.
B. Planes of the Human Body:
1. Sagittal plane-vertical plane that divides the body or an organ into right and left sides.
a. Median plane-divides the body or an organ into equal right and left sides.
b. Paramedian plane-divides the body or an organ into unequal right and left sides.
2. Frontal (Coronal) plane-divides the body or an organ into anterior and posterior portions.
3. Transverse (Cross-Sectional) plane-divides the body or an organ into superior and inferior
portions.
4. Oblique plane-divides the body or an organ at an angle.
VI. BODY CAVITIES-confined spaces in the body that contain the internal organs.
A. Cavities support, separate and protect the internal organs.
B. Major Cavities in the Human Body:
1. The Dorsal Body Cavity-located near the back surface of the body. Subdivisions of the
Dorsal Body Cavity:
a. The Cranial Cavity-formed by the cranial bones. This cavity contains the brain.
b. The Vertebral (Spinal) Cavity-formed by the vertebrae and this cavity houses the
spinal cord.
c. The cranial cavity and vertebral cavity are covered by a three-layered membrane
known as the meninges. The outer membrane attaches to the wall of the cavity and
the inner membranes adhere tightly to the brain and spinal cord.
2. The Ventral Body Cavity-located near the front surface of the body. The organs in this
cavity are referred to as viscera. Subdivisions of the Ventral Body Cavity:
a. The Thoracic Cavity-superior portion of the ventral body cavity. This cavity forms
the chest.
1) Compartments within the Thoracic Cavity:
a) Pleural cavities-2 of these; 1 around each lung.
b) Pericardial cavity-space that contains the heart. The pericardium is a
membrane in this cavity that surrounds and protects the heart.
c) The Mediastinum-the open space in the thoracic cavity excluding
the above cavities.
2) Thin-layered serous membranes cover the cavities and organs associated
with the thoracic cavity. These membranes are organized into two layers:
an outer parietal layer and an inner visceral layer (that attaches to the
organ). The space between these two layers is filled with a small amount of
serous fluid which reduces friction between the two layers of the
membrane. These serous membranes are often named for what they cover.
For example, the visceral and parietal pleura cover the lungs; while the
visceral and parietal pericardium surrounds the heart.
b. The Abdominopelvic Cavity-is separated from the thoracic cavity by the
diaphragm.
1) Subdivisions of the Abdominopelvic Cavity
a) Abdominal Cavity-contains the stomach, liver, small and large intestines.
1) This cavity is lined by a special membrane known as the
peritoneum. The peritoneum is organized into two distinct
layers: a parietal layer (that attaches to the wall of the
cavity) and a visceral layer (that adheres directly to the
organs of the abdominal cavity). Over some organs, the
visceral layer can form thick, protective coverings that are
referred to as mesenteries.
a) The space between the parietal and visceral layers is
known as the peritoneal cavity and it contains a
small amount of a lubricating fluid known as
peritoneal fluid.
b) Pelvic Cavity-contains the urinary bladder, rectum and the
reproductive structures.
2) The Abdominopelvic Cavity is divided into quadrants and regions which
helps health care professionals accurately identify specific areas within
each of these cavities. Professionals can palpate (feel) or auscultate (listen)
the abdominopelvic cavity to examine it.
a) Four Quadrants in the Abdominopelvic Cavity
b) Nine Regions of the Abdominopelvic Cavity
C. Other Cavities in the Body:
1. Oral cavity
2. Nasal cavity
3. Inner ear cavity
4. Gastrointestinal tract
VII. Like other organisms, humans exhibit all of the fundamental processes of life. For example, humans
can grow, obtain energy, reproduce, etc.
A. Metabolism-term that refers to the sum of all of the reactions that occur in the body.
1. Many of the reactions that occur in the human body are associated with either
generating or using energy.
2. Two Sets of Reactions that occur in the Human Body:
a. Anabolic Reactions-refers to reactions that build up complex molecules and
structures in the body.
b. Catabolic Reactions-refers to reactions that break down complex molecules and
structures in the body.
VIII. SURVIVAL NEEDS-these are essential for the maintenance of human life.
A. Nutrients-obtained from food. These are used for the production of energy and cell building
in the body.
B. Oxygen-is required for aerobic cellular respiration to occur. This process generates ATP
(cellular energy) for cells.
C. Water-accounts for approximately 60% of total body weight. Numerous chemical reactions
occur in the liquid environment of the human body.
D. Body Temperature-must be maintained at or near 98.6 degrees F (37 degrees C). This is the
optimal temperature at which most life maintaining reactions occur efficiently.
E. Atmospheric Pressure-is required for breathing to occur.
IX. HOMEOSTASIS-the ability of the body to maintain a stable internal environment. It is a state of
equilibrium in which conditions in the body remain within certain limits.
A. Any disruption of homeostasis in the body can lead to serious illness or even death.
B. Fortunately, the human body has a variety of devices that allow it to maintain homeostasis.
C. An individual is in homeostasis when:
1. It has an optimum body temperature (98.6 degrees F).
2. It contains an optimum level of body fluid.
3. It contains an adequate supply of minerals, vitamins and gases.
D. Stress-any stimulus (change) that creates an imbalance in the internal environment of the
human body.
1. Stress acts to disturb homeostasis within the human body.
2. A stress can be internal or external. Stresses can include heat, cold, low sugar levels.
3. The body has the ability to respond to stimuli in an effort to reestablish homeostasis.
4. 2 Systems in the body that Aid in Maintaining Homeostasis:
a. The Nervous System-which includes the brain, spinal cord and nerves. This
system produces and carries impulses throughout the body.
b. The Endocrine System-includes glands that secrete various chemicals and
hormones.
1) These 2 systems often work together to maintain homeostasis for the
body.
E. Feedback Systems (Loops)-a cycle of events that acts to maintain homeostasis within the body.
1. Components of a Feedback System:
a. The Receptor-monitors changes in the controlled conditions and sends
information regarding changes to the control center.
1) Stimulus-any stress that changes a controlled condition.
2) The receptor sends input to the control center.
b. The Control Center-regulates homeostasis; as well as the feedback systems that
govern homeostasis. The brain is the control center in the human body.
c. Effectors-receive information from the control center and produce a response.
Muscles and glands are the major effectors in the human body.
2. Types of Feedback Systems in the Human Body:
a. Negative Feedback Systems-respond by reversing the effects of a stimulus.
1) These systems maintain conditions within certain physiological limits.
2) These systems return the body to an ideal homeostatic condition.
3) Examples of a Negative Feedback System:
a) Body temperature
b) Blood pressure
b. Positive Feedback Systems-function by enhancing the original stimulus.
a) Examples of Positive Feedback Systems:
1) Blood clotting
2) Contraction of uterine muscles during pregnancy
X. MEDICAL IMAGING-allows physicians to examine the internal portion of the human body. Medical
imaging techniques allow physicians to detect disorders, defects and diseases of the human body.
A. Medical Imaging Techniques
1. Radiography (X-Rays)-the use of X-rays to produce images of the internal structures of the
human body. This technique is excellent for discovering fractures; however, organs often
appear as a blur on X-rays.
2. Computed Tomography Scanning (CT Scan)-the use of X-rays and computers to produce
3-dimensional images of body structures. It is used to detect kidney stones and tumors.
3. Xenon CT-CT brain scan enhanced with Xenon gas which allows for tracing blood flow.
This is used to identify strokes.
4. Dynamic Spatial Reconstruction (DSR)-specialized X-ray machine that produces
3-dimensional, moving images of internal structures. This is excellent for examining the
heart, blood vessels and the lungs.
5. Digital Subtraction Angiography (DSA)-an instrument used to examine blood vessels
before and after a dye has been injected into the bloodstream. This is used to detect
blocked blood vessels.
6. Positron Emission Tomography (PET)-the use of radioactive particles to produce images of
internal organs. This can provide some indication of organ function as well as structure.
7. Magnetic Resonance Imaging (MRI)-the use of radio waves and magnets to produce 3-
dimensional images of internal structures. It is not used on pregnant women or individuals
that have a pacemaker due to the use of magnets.
8. Ultrasound-sound waves are forced into the body where they are reflected by various
organs and tissues. These reflected sound waves are used to produce images of internal
structures.
a. Sonogram-the images produced by an ultrasound.
b. These are often used to follow the development of a fetus during pregnancy.
9. Mammogram-used to identify cysts and tumors within the breast. I. CHEMISTRY-the science dealing with the properties and transformations of matter.
II. MATTER-anything that occupies space and has a mass. Matter can exist in one of three
forms: as a solid, liquid or gas.
A. Components of Matter
1. Atoms-smallest functional units of matter.
a. Elements-cannot be broken down into smaller particles by chemical
reactions. There are 92 natural elements. Those that are required in
large supply for organisms to survive and live are known as Essential
Elements (these include Hydrogen, Nitrogen, Carbon, Oxygen).
2. Molecules-2 or more identical atoms that are bonded together.
III. ATOMS-the smallest functional units of matter. All chemical activities revolve around the
properties of atoms.
A. 3 Subatomic Particles that Make Up Atoms
1. Protons-are located in the nucleus (center) of an atom. They have a positive
charge.
2. Neutrons-located in the nucleus and have a neutral charge.
3. Electrons-are located in orbitals (shells) and they have a negative charge.
a. Different atoms have different numbers of electrons and electron
orbitals.
b. Number of Electrons per Orbital
1) First Orbitals-can contain no more than 2 electrons.
2) Second Orbitals-can contain no more than 8 electrons.
3) Third Orbitals-can contain no more than 8 electrons.
c. Atoms attempt to fill their outer orbital with the maximum number of
electrons. Atoms accomplish this through a process known as bonding.
In bonding, atoms can either gain, lose or share electrons with other
atoms.
d. Stable atoms-have an outer orbital that is filled with the maximum
number of electrons.
B. Important Atomic Terms
1. Atomic Number-the number of protons in an atom. Each element has its own
specific atomic number.
a. The number of protons in an atom is equal to the number of electrons in
the atom.
2. Mass Number-the number of protons plus the number of neutrons in the atom.
3. Isotopes-atoms of the same element that contain the same numbers of protons
and electrons but that contain different numbers of neutrons.
a. Hydrogen Isotopes
b. Radioactive Isotopes-decay spontaneously giving off high energy radiation.
C. The Periodic Table of the Elements-is a list of all of the known elements.
1. The table is organized by increasing atomic number. Can you read the Table?
IV. CHEMICAL BONDING-attractive forces that hold 2 or more atoms together.
A. Chemical bonding allows atoms to fill their outer orbitals with the maximum number
of electrons. This allows atoms to become stable.
B. 2 Types of Chemical Bonds: Ionic Bonds, Covalent Bonds
C. Ionic Bonding-occurs when one atom loses an electron and a second atoms gains the
electron.
1. This type of bonding produces ions-charged particles.
2. Oxidation-refers to the loss of an electron. Atoms that lose an electron are said
to be oxidized. Atoms that are oxidized are written with a positive charge. Why
is this so?
3. Reduction-refers to the gain of an electron. Atoms that gain an electron are said
to be reduced. Atoms that are reduced are written with a negative charge. Why
is this so?
4. Sodium Chloride (NaCl)-an example of an ionic bond.
D. Covalent Bonding-occurs when atoms share 1 or more pairs of electrons.
1. There are no charges associated with covalent bonds.
2. These are often very strong bonds.
3. Examples of Covalent Bonds:
4. Double Covalent Bonds-occur when atoms share 2 pairs of electrons.
5. Triple Covalent Bonds
6. Polar Covalent Bonds-in these bonds, one atom shares the electron stronger than
another atom, thus, the atom has a slightly negative charge. Polar molecules tend
to react easily with other molecules. Due to this, polar molecules are said to be
hydrophilic (meaning that they dissolve in water).
F. Weak Attractions between atoms:
1. Hydrogen bonds-sometimes hydrogen atoms that are covalently bonded to one
atom can form a weak attraction (with no electrons involved) with atoms in
other molecules.
2. Van der Waals Interactions-very weak attractions that form between slightly
positive and slightly negative molecules.
G. Bond Strength:
1. Covalent Bonds-strongest bonds
2. Ionic Bonds
3. Hydrogen Bonds
4. Van der Waals Interactions-weakest molecular interactions
H. Types of Reactions Related to Bonding that occur in the Human Body:
1. Synthesis Reactions-occur when atoms bond together to form larger molecules.
2. Decomposition Reactions-occur when molecules are broken down into smaller
molecules or atoms.
3. Exchange Reactions-occur when molecules exchange atoms with each other.
V. WATER
A. Water is the most abundant compound in all living organisms. Many of the reactions
that occur in living organisms occur or require water to take place. Without water,
living things (including both plants and animals) would die.
B. Structure of a water molecule
1. Water molecules are composed of 2 hydrogen atoms that are covalently
bonded to a single oxygen atom. What type of bond is this?
a. Overall, water has a very strong and stable structure.
C. Properties of Water
1. Water is a Polar Molecule-this means that the Oxygen atom tends to have a
stronger attraction for the electrons in the covalent bond than do the Hydrogen
atoms. Due to this, the oxygen is slightly more negative than the hydrogens.
Polar molecules tend to react easily with most other molecules.
a. Hydrophilic Compounds-are soluble in water. These compounds
dissolve in water. Examples of hydrophilic compounds include:
b. Hydrophobic Compounds-are not soluble in water. These compounds
do not dissolve in water. Examples include:
2. Water Forms Hydrogen Bonds
a. Hydrogen Bonds-weak attraction between the hydrogen atoms of one
water molecule and the oxygen atom of a second water molecule.
3. Water Stabilizes Temperature
a. Water has a very stable temperature. It takes a tremendous amount of
energy to heat water and a great deal of cold to freeze water.
b. This protects living organisms from rapid temperature changes.
4. Water Participates in Many Reactions
a. Many important biological reactions occur in water. Also, water
initiates many reactions.
5. Water is a powerful solvent. A solvent is a fluid that molecules can dissolve in.
VI. ACIDS, BASES, and pH
A. Acids-release hydrogen ions (H+) when placed in water.
B. Bases-release hydroxide ions (OH-) when placed in water.
C. pH Scale-a measure of how acidic or basic a compound is.
1. Neutral, Strong Acid vs. Weak Acid, Strong Base vs. Weak Base
2. In the real world, small changes in pH can have severe effects on living
organisms. Due to this, most organisms have methods that allow them to
maintain a normal, healthy pH.
D. Buffers-compounds that reduce or minimize changes in pH. These help to maintain a
stable pH.
1. Bicarbonate Buffer System-a major buffering system in living organisms.
a. H2CO3 HCO3 + H+
(Carbonic Acid) (Bicarbonate) (Hydrogen ion)
b. How Bicarbonate Buffers a System
1) In acids (when extra hydrogen ions are present), bicarbonate
will soak up the hydrogen ions to produce a weak acid. This
raises pH towards neutrality.
2) In bases, the hydrogen ions can react with extra hydroxyl ions
to produce water which has a pH of 7. Overall, this lowers pH.
VII. ORGANIC MOLECULES-are molecules that contain the elements carbon and hydrogen.
A. There are four major organic Macromolecules found in all living organisms:
carbohydrates, lipids, proteins and nucleic acids. Often times, numerous smaller
molecules (known as monomers) form covalent bonds to produce larger
macromolecules.
B. Types of Reactions associated with Polymers:
1. Dehydration (Condensation) Reactions-reactions in which monomers bond
together to produce macromolecules. Water is typically lost in these reactions.
2. Hydrolysis Reactions-reactions in which macromolecules are broken down into
monomers.
VIII. Carbohydrates-sugars and related compounds.
A. All carbohydrates are composed of Carbon, Hydrogen and Oxygen. In carbohydrates,
there is always a 1:2:1 ratio of carbon to hydrogen to oxygen.
B. Classes of Carbohydrates:
1. Monosaccharides-simple sugars
a. These serve as monomers for many of the larger carbohydrates.
b. Glucose is an example of a monosaccharide.
2. Disaccharides-sugars that are composed of 2 monosaccharides that are
covalently bonded together. These are formed by dehydration reactions.
a. Types of Disaccharides
1. Sucrose-table sugar
2. Lactose-milk sugar
3. Maltose-sugar found in beer
3. Polysaccharides-sugars that are composed of more than 2 monosaccharides that
are covalently bonded together. These are often very large molecules.
b. Types of Polysaccharides
1. Starch-a stored form of glucose in plant cells. Plants can use starch
for energy under times of need or stress.
2. Glycogen-the storage form of glucose in humans. Humans can
convert glycogen into glucose under times of need or stress. This
glucose can then be used as an energy source. Glycogen is stored in
the liver and in some muscle fibers.
IX. Lipids-fats, oils, waxes.
A. All lipids are hydrophobic-they do not dissolve in water.
B. Lipids serve as a source of stored energy in the human body. Fats also protect and cushion
structures in the human body.
C. Structure of a Typical Lipid
1. Lipids are composed of 2 major components:
a. Glycerol-a 3 carbon alcohol that forms the backbone of a lipid.
b. Fatty Acids
1) Three fatty acid molecules attach to glycerol to form a lipid. Each
fatty acid replaces the hydrogen atom on the hydroxyl groups of the
glycerol molecule. Due to this, there is one fatty acid bonded to
each carbon atom of the glycerol molecule.
a) Due to this arrangement, lipids are often referred to as
triglycerides.
c. Saturated vs. Unsaturated Fatty Acids
D. Types of Lipids
1. Phospholipids-contain only 2 fatty acid tails. These are found in cell membranes.
They have hydrophilic heads and hydrophobic tails.
2. Hormones-chemicals that regulate the growth and functioning of living organisms.
3. Steroids-there are several different types of steroids:
a. Cholesterol-common steroid. This can be used to produce Vitamin D but
large supplies of cholesterol in the diet can cause heart disease.
b. Sex Hormones-including testosterone and estrogen.
X. Proteins
A. Proteins are composed of many amino acids that are covalently bonded together. These
bonds are referred to as peptide bonds.
B. Amino Acids-there are 20 naturally occurring amino acids. They can bond in a variety
of sequences to produce proteins.
a. All amino acids contain a central carbon atom that is bonded to a hydrogen
atom, a carboxyl group (COOH) and an amino group (NH2). The remaining
carbon bond can form with numerous other molecules to actually produce
a specific amino acid.
b. Some common amino acids include: phenylalanine, tryptophan, asparagine
C. Levels of protein Structure:
a. Primary Structure-a linear sequence of bonded amino acids.
b. Secondary Structure-coils and slight folding of amino acid structure that
is supported by hydrogen bonds.
c. Tertiary Structure-complex, three-dimensional structure of folded amino
acids.
d. Quaternary Structure-aggregation of multiple proteins into a complex
structure.
D. Proteins serve primarily as structural compounds in living organisms. They also make up
enzymes which are proteins that speed up biological reactions. Reactions associated with
enzymes occur at the active site of an enzyme. The molecule that an enzyme reacts with is
known as the substrate.
VII. Nucleic Acids
A. These are composed of nucleotides that are covalently bonded together.
B. Individual Nucleotides Contain:
1. A 5 Carbon Sugar
2. A Phosphate group
3. A Nitrogen-containing base
C. Types of Nucleic Acids:
1. Deoxyribonucleic Acid (DNA)-primary genetic material in living organisms.
2. Ribonucleic Acid (RNA)-involved in building proteins for living cells.
3. Adenosine Triphosphate (ATP)-major energy source for cells.
I. Today, scientists know that all living organisms are composed of cells.
A. Cells are defined as the smallest living, functional units in living organisms.
B. Cells come in a variety of sizes and shapes; however, most cells are extremely
small and can only be seen with the aid of a microscope.
C. Human cells are described as being Eukaryotic. This means that these contain a
membrane bound nucleus and multiple organelles.
II. STRUCTURE OF HUMAN CELLS
A. Plasma Membrane-outer covering around a cell; these regulate what materials can enter
or exit the cell. Plasma membranes are composed of a phospholipid bilayer and proteins.
Plasma membranes are described as being semipermeable, meaning that they only allow
some things to pass through.
1. Movements through Plasma Membranes
a. Diffusion-the random movement of molecules from areas of greater
concentration to areas of lesser concentration. No energy is required for
this process to occur; therefore, it is known as a passive process.
b. Osmosis-the diffusion of water across the plasma membrane. This is also a
passive process. The water moves from where it is more concentrated to
where it is less concentrated.
1) Three types of solutions based on osmosis:
a) Isotonic solutions-no net movement of water molecules.
b) Hypertonic solutions-water moves out of the cell.
c) Hypotonic solutions-water moves into the cell.
c. Facilitated Diffusion-passive process in which plasma membrane proteins
move molecules through the membrane.
d. Active Transport-requires energy to occur. An example is the Sodium-
Potassium Pump in nerve cells. These processes move molecules from
lesser to greater concentrations.
B. Cytoplasm-a semifluid that contains cytosol (cellular fluid-primarily water).
C. The Major Cellular Organelles
1. The Nucleus-largest and most distinct organelle. It makes up 5-10% of the total
volume of the cell. It is typically round in shape. This structure functions by
regulating all cellular activities.
a. The nucleus stores a cell’s supply of DNA.
1) Chromatin-a compound composed of DNA and proteins. In dividing
cells, chromatin condenses to form chromosomes which contain
genes.
2) The Nuclear Envelope-a double-layered membrane that surrounds
and protects the nucleus. These have nuclear pores that allow
materials to pass through.
b. The Nucleolus-a structure located in the nucleus. RNA and proteins are
produced here.
2. The Endomembrane System-consists of the following:
a. The Endoplasmic Reticulum (E.R.)-a series of continuous membranes
within the cell. 2 Types of E. R.
1) Rough Endoplasmic Reticulum-is covered with ribosomes which
produce proteins.
2) Smooth Endoplasmic Reticulum-lacks ribosomes.
a) This structure is involved in lipid synthesis and detoxifying
cells.
b. The Golgi Complex-a set of flat discs in eukaryotic cells. This structure functions by packaging and removing wastes from the cell and processing
some sugars and fats for cells.
c. Lysosomes-membrane-bound organelles that contain digestive enzymes
that breakdown carbohydrates, lipids and proteins.
3. Mitochondria-slipper-shaped organelles found in all cells.
a. These are involved in the conversion of glucose into ATP (through a process
known as Aerobic Cellular Respiration).
b. These require an input of oxygen to function properly, thus they are referred to as
being aerobic.
c. Most cells contain numerous mitochondria.
4. The Cytoskeleton-a series of protein fibers found in all eukaryotic cells. These fibers
provide support to the cell and they serve as sites of attachment for the
organelles.
a. The cytoskeleton is made up of support cylinders known as microtubules. 5. Organelles involved in movement:
a. Flagella-long, thread-like structures.
b. Cilia-short hair-like structures.
6. Cell Junctions-points of attachment between cells. Types of Cell Junctions
Include:
a. Tight Junctions-the cell membranes are pressed against each other.
b. Gap Junctions-form channels between two cells. Are common in nerve
cells.
c. Desmosomes-act like rivets between cells.
III. MITOSIS-the process through which most cells reproduce themselves by dividing in half. In this
process, the new cells produced are genetically identical to the original cell.
I. TISSUES-groups of cells located in a distinct region of the body that work together to carry out
a specific function.
A. Histology-the study of tissues.
B. Tissues differ from each other based on the types of cells that they contain and the
specific functions of those cells.
C. Tissues are most effectively observed using microscopes. In most cases, small tissue
sections are removed from the body, stained and prepared for observation on a
microscope slide.
II. TYPES OF TISSUES IN THE HUMAN BODY:
A. Epithelial Tissue
B. Connective Tissue
C. Muscle Tissue
D. Nerve Tissue
III. EPITHELIAL TISSUE (Epithelium-singular)-typically occurs as a sheet of cells that covers or lines
surfaces and cavities in the body.
A. General Features of Epithelial Tissue
1. The cells of epithelium are arranged in sheets and are packed closely together.
2. It is avascular-does not contain blood vessels. Epithelial cells are nourished by
nutrients that diffuse from blood vessels in the underlying connective tissue.
3. Epithelium has a nerve supply.
4. Epithelium has a high regeneration rate. Cell division occurs rapidly in epithelial
cells. This allows epithelial tissue to heal quickly.
5. Epithelial tissue has several major functions in the body including: protection,
absorption, filtration, excretion, secretion and sensory reception.
6. Nearly all substances received or given off by the body must pass through a layer of
epithelial tissue.
7. Two broad categories of epithelial tissue: Covering and Lining Epithelium and
Glandular Epithelium. We will focus on covering and lining epithelium in this
chapter-glandular epithelium will be covered when get to the Endocrine System.
B. Structure of Epithelial Tissue:
1. The Apical Surface-upper, free surface of epithelial tissue that is exposed to the
exterior or to a body cavity. This layer may contain fingerlike projections called
microvilli or hairlike structures known as cilia. Collectively, these structures are
referred to as a brush border and they aid in increasing the surface area of the
tissue.
2. All epithelial tissues rest upon and are supported by connective tissue.
a. Basement membrane-a layer of attachment between epithelial and
connective tissue. This structure functions by holding epithelial tissue in
place. This membrane also plays a key role in regulating the movement of
materials between the epithelium and the lower connective tissue.
1) 2 Layers of the Basement Membrane:
a) Basal lamina-secreted by the epithelial tissue. This layer
acts as a filter that determines which molecules will diffuse
from the underlying connective tissue. This layer is
composed primarily of proteins and sugars, thus it is
acellular.
b) Reticular lamina-secreted by connective tissue. This layer
functions by providing support to the overlying epithelial
tissue.
C. Organization of Cells in Epithelial Tissue
1. Arrangement of Cells in Epithelial Tissue
a. Simple epithelium-is only one cell layer thick. This type of epithelium is
found in areas where absorption, filtration and osmosis occur.
b. Stratified epithelium-is composed of two or more cell layers. This type of
epithelium is found in areas where protection is important.
c. Pseudostratified epithelium-has the appearance of being several cell layers
thick; however, it is only one cell layer thick.
2. Cell Shapes in Covering and Lining Epithelium
a. Squamous cells-are flat and scalelike.
b. Cuboidal cells-are boxlike, almost as tall as they are wide.
c. Columnar cells-are column or rectangular in shape.
d. Transitional cells-have the ability to change shape.
D. Two Broad Categories of Covering and Lining Epithelial Tissue (both are further subdivided
into specific types).
1. Simple Epithelium
2. Stratified Epithelium
E. Specific Types of Surface Epithelium
1. Simple squamous epithelium-composed of a single layer of flat cells.
a. Is a very thin tissue, so it is highly adapted for diffusion and filtration.
b. Forms endothelium, which lines blood vessels and many of
the hollow organs of the body.
c. Mesothelium-serous membrane that covers the ventral body cavity.
2. Simple cuboidal epithelium-lines glands and is involved in secretion and
absorption. This tissue is also found in the kidney tubules.
3. Simple columnar epithelium
a. Can be nonciliated (as in the gallbladder) or ciliated.
b. Is often covered by microvilli.
c. This tissue lines the digestive system from the mouth to the anus.
d. This type of tissue often contains goblet cells which produce mucus.
F. Specific Types of Stratified Epithelium:
1. Stratified Squamous Epithelium
a. This tissue can be keratinized (covered by the thick protein keratin) or
nonkeratinized.
b. Keratinized squamous epithelium makes up the bulk of the epidermis while
nonkeratinized squamous epithelium forms a covering over the tongue.
2. Stratified Cuboidal Epithelium-lines the sweat glands and a portion of the ovaries.
G. Pseudostratified epithelium-looks thick but is only one cell layer thick.
1. Pseudostratified columnar epithelium-located in the trachea and nasal cavity this
tissue can contain:
a. Goblet cells
b. Cilia
IV. CONNECTIVE TISSUE-the most abundant type of tissue in the human body.
A. Functions of Connective Tissue
1. Binds structures together
2. Provides support
3. Protects, provides immunity
4. Insulates, pads
5. Transports materials through the body
6. Movement
B. General Features of Connective Tissue
1. Has an extensive nerve supply
2. Most types are highly vascular
C. Structure and Organization of Connective Tissue
1. Connective Tissue is composed of three basic elements:
a. Cells-make up the bulk of most connective tissues.
1) The suffix blast refers to unspecialized, immature types of connective
tissue. EX: fibroblasts
2) The suffix cyte refers to mature types of connective tissue cells.
b. Fibers-provide support and strength to connective tissue. Collagen fibers,
elastic fibers and reticular fibers are three major types of fibers found in
connective tissue.
c. Matrix-the material that surrounds connective tissue cells. This material is
noncellular.
1) It can be fluid, gelatinous or solid.
2) Ground substance-fills the spaces around the connective tissue cells.
It is composed of matrix and fibers.
D. Mesenchyme-embryonic connective tissue. This type of tissue develops early in embryonic
development and specializes into the different connective tissues that make up the body.
Some mesenchyme tissue remains in the human body throughout our lives.
E. Types of Connective Tissue in the Body:
1. Areolar Connective Tissue-contains all three types of connective tissue fibers. This
tissue provides strength, support and elasticity to body structures. It is commonly
found beneath epithelial tissue.
a. It also serves as a packaging tissue in the body. When a body area becomes
inflamed, areolar tissue soaks up the excess fluid to prevent edema.
b. Areolar tissue is classified as a type of loose connective tissue since the fibers
in this tissue are loosely arranged. Areolar tissue can be stronger than steel.
2. Adipose Tissue-fat tissue.
a. Adipocytes-mature cells in adipose tissue. These cells are specialized for fat
storage. The fat is stored in a fat vacuole.
b. Adipose tissue functions as an insulator, a source of stored energy and as a
padding around body structures.
c. Adipose is also classified as a loose type of connective tissue.
d. Subcutaneous layer-composed of areolar and adipose tissue. This layer
attaches the skin to the underlying tissues and organs.
3. Reticular Tissue-contains only reticular fibers. It is a form of loose connective tissue. a. Is very common in lymph nodes, the spleen and bone marrow. This tissue holds
structures together and it can form a framework for blood cells to attach to.
4. Dense Regular Connective Tissue-fibers in this tissue are packed tightly together, thus,
it is referred to as being a dense type of connective tissue.
a. Typically contains collagen fibers which offer a great deal of strength to this
tissue. That said, this tissue provides strength, support to body structures.
c. Tendons-composed of dense regular connective tissue. These are connective
tissue cords that attach muscles to bone.
5. Dense Irregular Connective Tissue-fibers in this tissue have an irregular arrangement.
Again, this is a type of dense connective tissue. This type of tissue typically forms sheets that cover and protect organs and structures within the body.
a. This tissue is found in heart valves and in the periosteum (membrane that
covers bone). It also forms fibrous coverings over some organs.
6. Cartilage-is composed of fibers that are packed tightly together. It can withstand a
great deal of stress.
a. Chondrocytes-mature cartilage cells. These are located in open spaces known
as lacunae.
1) Matrix surrounds the lacunae.
2) Perichondrium-the membrane that surrounds cartilage tissue.
3) Cartilage has a greatly reduced blood supply and nerve supply. Due to
this is a very slow growing and healing type of tissue.
b. Chondroblasts-these are cells that secrete new cartilage matrix. These
develop into chondrocytes.
c. Types of Cartilage Tissue:
1) Hyaline Cartilage-most abundant type of cartilage in the body. It is
located at the ends of long bones. Hyaline cartilage greatly reduces
friction and it absorbs shock at the ends of bones. This type of cartilage
also makes up the bulk of the embryonic skeleton and it forms the
epiphyseal plates of bones. This is also referred to as articular cartilage.
2) Elastic Cartilage-is very similar to hyaline cartilage in structure. This
tissue forms the bulk of the ears, nose, glottis (voice box), and
epiglottis (flap that covers the trachea).
3) Fibrocartilage-typically forms pads in the human body. Can withstand
extreme pressure. Intervertebral discs and the pubic symphysis are
examples of fibrocartilage in the body.
7. Bone (Osseous) Tissue-due to its hardness, bone has the ability to support and protect
body structures. Along with cartilage, bone forms the skeleton of the body.
a. 2 Types of Bone Tissue:
1) Compact Bone-forms the external covering over all human bones.
a) This type of bone is composed of repeating units known as
Haversian Systems (Osteons).
b) Components of Haversian Systems:
1) Osteocytes-mature bone cells; are located in lacunae.
2) Lamella-rings of matrix. This matrix is composed of
mineral salts (which can be calcium carbonate or
calcium phosphate).
3) Canaliculi-small canals that extend from lacunae,
through the lamellae of bone. Nutrients and wastes pass
to/from osteocytes through these small canals.
4) Haversian (Central) Canals-holes in the center of each
Haversian System. These openings contain blood vessels
and nerves.
2) Spongy Bone-is not composed of Haversian Systems. This type of
bone is composed of thin plates of bone known as Trabeculae.
Trabeculae are composed of osteocytes and lamellae.
8. Blood-has a liquid matrix.
a. Components of Blood:
1) Plasma-the liquid portion of blood. This is the matrix of blood. Plasma
contains a variety of dissolved compounds.
2) Formed Elements-cells and cell fragments in blood. The formed
elements in blood include the following:
a) Erythrocytes (Red Blood Cells)-involved in carrying oxygen to
body cells and carbon dioxide to the lungs. These lack a nucleus
and cannot divide. They do contain the red pigment hemoglobin.
b) Leukocytes (White Blood Cells)-function in fighting infection and
in providing immunity to the body. These do have a distinct
nucleus they can divide.
c) Thrombocytes (Platelets)-involved in blood clotting.
V. MUSCLE TISSUE-is composed of fibers that are capable of generating force for contraction.
A. The functions of muscle tissue include moving bones, providing body support and protection
and thermogenesis (heat production).
B. Muscle tissue is composed of numerous cells known as muscle fibers.
C. Types of Muscle Tissue in the Human Body:
1. Skeletal Muscle Tissue-attaches to and moves bones.
a. Is classified as being striated and voluntary.
2. Cardiac Muscle Tissue-located in the wall of the heart.
a. Is striated and involuntary.
b. Contains intercalated discs-swellings of the cell membrane of cardiac muscle
fibers. These hold cardiac muscle fibers together during muscle contraction.
3. Smooth Muscle Tissue-is located in the internal organs and blood vessels of the body.
a. Is nonstriated and involuntary.
VI. NERVOUS TISSUE-makes up the brain, spinal cord and nerves of the nervous system.
A. 2 Types of Cells in Nervous Tissue:
1. Neuroglia (Support Cells)-support, insulate and protect the nervous system.
2. Neurons-the primary types of nerve cells. These are capable of generating and
conducting impulses (electrical signals) throughout the body. Neurons cannot divide.
a. These function by responding to stimuli via impulse formation and conduction.
VII. TISSUE REPAIR-the process by which tissues replace dead or damaged cells.
A. Tissue repair can occur in two major ways:
1. By Regeneration-the replacement of destroyed tissue with the same kind of tissue.
2. By Fibrosis-the formation of fibrous connective tissue (Scar tissue) over injured tissue.
B. Epithelial and connective tissues have a high capacity for continuous renewal.
C. Muscle tissue repair can occur; however, it is generally a slow process.
D. Nerve tissue does not have much capacity for renewal.
VIII. TISSUE GROWTH
A. Hyperplasia-tissue growth that occurs as cells increase their number. Epithelium grows in this
fashion.
B. Hypertrophy-tissue growth that occurs as preexisting cells enlarge in size. Adipose and muscle
tissue exhibit this type of growth.
C. Neoplasia-development of a tumor (either benign or malignant). The tumor is known as a
neoplasm (new growth).
D. Metaplasia-occurs when one type of tissue changes to another type of tissue (ciliated
epithelium in smokers often changes to a stratified form of epithelium).
IX. TISSUE DEATH
A. Necrosis-premature, pathological death of tissue to trauma, toxins or infection.
B. Infarction-tissue due that occurs when blood supply is cut off to the tissue.
C. Gangrene-results from infection or interrupted blood supply.
1. Decubitus ulcer
X. MEMBRANES IN THE HUMAN BODY-these cover and protect surfaces and structures in the body.
A. Types of Membranes in the Human Body:
1. Epithelial Membranes-composed of epithelial tissue and an underlying connective
tissue layer. Types of Epithelial Membranes Include:
a. Cutaneous Membrane-refers to the skin.
b. Mucous Membranes-line body cavities that open to the exterior of the body.
1) This includes the digestive, respiratory and urogenital tracts. All of
these systems are moist areas in the body.
2) These membranes are adapted for filtration, absorption and secretion.
3) These membranes often contain special secretory cells such as goblet
cells.
4) They form a protective barrier to prevent bacterial and viral invasion of
systems in the body.
c. Serous Membranes-line body cavities that do not open directly to the outside
of the body. These often cover organs in the body. These are composed of simple
squamous epithelium that covers a layer of areolar connective tissue.
1) These are made up of 2 distinct layers:
a) The Parietal Layer-attaches to the walls of body cavities.
b) The Visceral Layer-attaches directly to and covers internal
organs.
2) Serous membranes secrete a special lubricating fluid known as
serous fluid which lubricates the surfaces of the parietal and visceral
layers so that they easily slide across one another.
3) Serous membranes are often named for the organ that they
cover. Examples of this include: the pericardium, the pleural membranes and the peritoneum.
2. Connective tissue membranes-Types:
a. Synovial Membranes-are composed entirely of areolar connective tissue. These
line joint cavities in the body. These membranes secrete synovial fluid which
lubricates the cartilage at the ends of long bones in the body.
b. Meninges-Cover and protect the brain and spinal cord.
XI. EMBRYONIC/DEVELOPMENTAL ASPECTS OF TISSUES
A. The major tissues of the human body develop from the primary germ layers (endoderm,
mesoderm, ectoderm) that form in embryonic development.
B. All of the primary tissues and organs are in place by the end of the second month of embryonic
development. These tissues will continue to develop throughout the period of development.