Anatomy, Physiology and Disease Chapter 3 The Cells: The Raw Materials and Building Blocks

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Anatomy, Physiology and Disease Chapter 3The
Cells The Raw Materials and Building Blocks
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Overview of Cells

• Cells are formed from chemicals and structures
• Cells are found in all living things
• Some nerve cells can be 2 feet long or longer
• Cells can be flat, round, thread like, or
  irregularly shaped
• 7.5 trillion cells found in body work together to
  allow for proper functioning of body

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Figure 3-1 Various types of cells within the
human body
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Cell Structure

• Certain common traits that almost all cells
  share
• Nucleus
• Organelles
• Cytoplasm
• Cell membrane

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Figure 3-2 Cellular components
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Cell Membrane

• Defined boundary that possesses a definite shape
  and actually holds cell contents together, acting
  as protective covering
• Allows material in and out of cell
• Selectively permeable because they choose what
  gets in or out
• 3/10,000,000 of an inch thick
• Example Electrolytes
• Na Sodium
• K Potassium
• Cl Chloride
• Co2 Carbon Dioxide

Na K Pump
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Figure 3-3 The cell membrane
Na K Pump
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Transport Methods

• Moving things in and out of cell can be done in
  two broad ways
• Passive transport requires no extra form of
  energy to complete
• Active transport requires some addition of
  energy to make it happen

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Transport Methods (contd)

• Passive transport can be divided into four types
• Diffusion
• Osmosis
• Filtration
• Facilitated diffusion

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Diffusion

• Most common form of passive transport in which
  substance of higher concentration travels to area
  of lesser concentration
• Examples
• Adding packet of powdered drink mix to pitcher of
  water
• Smell of classmates perfume filling room
• Necessary to move oxygen from lungs to blood
  stream, or carbon dioxide from blood stream to
  lungs

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Figure 3-4 Two examples of diffusion
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Osmosis

• Another form of diffusion in which water travels
  through selectively permeable membrane to
  equalize concentrations of a substance
• Dissolved substance called a solute

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Osmosis cont

• Water tends to travel across a membrane to
  equalize concentrations of a solute ability of
  substance to pull water toward area of higher
  concentration called osmotic pressure
• The greater concentration of solute, the greater
  osmotic pressure, or pull, it exerts to bring in
  water

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Filtration

• Differs from osmosis in that pressure is applied
  to force water and its dissolved materials across
  membrane
• Similar to rush of people pushing through
  turnstile during rush hour
• Example pumping of heart, which forces blood
  flow into kidneys, where filtration takes place

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Figure 3-6 The process of filtration in the
kidneys, where smaller solutes such as the
electrolytes sodium and potassium pass through
the membrane, while the larger blood protein and
cells normally do not.

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Facilitated Diffusion

• A variation of diffusion in which a substance is
  helped in moving across the membrane, similar to
  an usher helping you to your seat
• Glucose is the substance that is often passed
  into our bodies
• It can be imagined as moving into an already
  revolving door once it steps into the door it
  is pushed along by Insulin.

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Pathology Connection Cystic Fibrosis

• Incurable, fatal genetic disease affecting 1/3000
  Caucasian babies

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Cystic Fibrosis (contd)

• Etiology malformation in membrane channels for
  chloride and sodium ions
• Sodium and chloride do not diffuse across cell
  membrane as they normally would
• Fluid around cells becomes extremely salty due to
  excess sodium and chloride
• Results in excessively thick mucus in
  respiratory, digestive, and reproductive systems
  mucus can cause clogging in organs

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Cystic Fibrosis (contd)

• S/S may include
• Difficulty breathing (SOB)
• Nutritional deficits due to decreased absorption
  of nutrients
• Increased risk of respiratory infection
• Diabetes
• Infertility (especially in males)

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Cystic Fibrosis (contd)

• RX
• No cure treatments help extend and improve
  quality of life
• Nutritional supplements
• Antibiotics to prevent pneumonia
• Mucus thinning drugs (Mucomyst-Ascetlsysteine)
• With treatment today, average life span of
  patient is 35 years

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Cystic Fibrosis (contd)

• Diagnosis
• Prenatal genetic testing
• Postnatal genetic testing
• Testing pulmonary function
• Testing amount of sodium in sweat

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Pathology Connection Diabetes Mellitus

• Lack of glucose transport into cells causes
  several problems
• Lots of glucose hangs around in bloodstream,
  causing big osmotic problems for cells
• Cells cant make as much energy as they need when
  glucose cant be transported

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Types of DM

• Type I results from the body's failure to produce
  insulin. 5-10 of diabetics have type I diabetes.
  Must take insulin to survive.
• Type II results from Insulin resistance, a
  condition in which cells fail to use insulin
  properly. Most Americans who are diagnosed with
  diabetes have type 2 diabetes
• Gestational Pregnant women who have never had
  diabetes before but who have high blood sugar
  (glucose) levels during pregnancy. Affects about
  4 of all pregnant women

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Endocytosis

• Used by cells for intake of liquid and food when
  substance too large to diffuse across membrane
• Examples
• Phagocytosis name for process if solid particle
  being transported
• Pinocytosis name for process if water being
  transported

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Exocytosis

• Transport of things out of cell
• Some cells produce substance needed outside cell
• Once substance is made, it is surrounded by
  membrane, forming a vesicle, and moves to cell
  membrane
• Vesicle becomes part of cell membrane and expels
  its load out of cell

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Pathology Connection Familial
Hypercholesterolemia

• Blood cholesterol too high caused by poor diet
  and exercise or inherited
• Normally low density lipoprotein (LDL or bad
  cholesterol) binds to cholesterol, and allows it
  to be carried into cells via endocytosis once
  inside, cholesterol used to make other lipids

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Familial Hypercholesterolemia contd

• LDL doesnt move into cells, and stays in blood
  causes 2 problems
• Too little cholesterol gets into cells, and cells
  must make more cholesterol
• LDL that cannot get into cells hangs around in
  blood causes plaques in blood vessels which can
  lead to blood clots, strokes, and heart attacks
• RX with diet modifications and cholesterol
  lowering drugs
• 1/500 Americans have moderate form

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Phagocytosis, Pinocytosis Exocytosis
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Cytoplasm

• Gel-like substance composed of water, nutrients,
  and electrolytes, which looks a lot like white of
  raw egg
• Required by cells for their internal environment
  to thrive and function

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Nucleus

• Brains of cell
• Dictates activities of other organelles in cell
• Has double walled nuclear membrane preventing
  materials from entering

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Nucleus (contd)

• Chromatin
• Contains deoxyribonucleic acid (DNA) DNA
  contains blueprints, or specifications, for
  creation of new cells
• Will eventually form chromosomes, which contain
  genes
• Genes determine our inherited characteristics

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Nucleus (contd)

• Nucleolus
• Spherical body made up of dense fibers found
  within cell nucleus
• Major function is to synthesize ribonucleic acid
  (RNA) that forms ribosomes

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Ribosomes

• Organelles found on endoplasmic reticulum or
  found floating around in cytoplasm
• Made of ribonucleic acid (RNA) and assist in
  production of enzymes and other protein
  substances needed for cell repair and
  reproduction
• Can be considered remodeler of cell, taking
  existing structure and maintaining and repairing
  it

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Centrosomes

• Act as building contractor, building new
  structures as need arises
• Contain centrioles that are involved in division
  of cell
• Centrioles are tubular shaped and usually found
  in pairs

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Mitochondria

• Tiny bean-shaped organelles, act as power plant
  to provide up to 95 of bodies energy needs for
  cellular repair, movement, and reproduction
• If cell needs more power, it increases number of
  mitochondria in cell
• Liver cells, which are quite active, have up to
  2,000 mitochondria in each cell

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Mitocondria contd

• Contain special enzymes that help to take in
  oxygen for use in producing energy
• Energy produced is in form of ATP (adenosine
  triphosphate) created by mitochondria

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Endoplasmic Reticulum

• Series of channels set up in cytoplasm that are
  formed from folded membranes
• Has two distinct forms
• One has sandpaper-like surface, with ribosomes on
  it, called rough endoplasmic reticulum
  responsible for synthesis of protein
• Second form has no ribosomes and appears smooth,
  called smooth endoplasmic reticulum synthesizes
  lipids and steroids

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Golgi Apparatus

• Looks like a bunch of flattened membranous sacs
• Once protein from the endoplasmic reticulum is
  received, it further processes and stores it
• Takes processed protein to cell membrane where it
  is released
• Salivary glands and pancreatic glands have higher
  numbers of Golgi apparati because they have
  higher level of secretion or storage

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Lysosomes

• Organelles containing powerful enzymes that take
  care of cleaning up intercellular debris and
  other waste
• Lysosomes help keep us healthy they destroy
  unwanted bacteria by participating in process of
  phagocytosis

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Other Interesting Parts

• Vesicles vans which take stuff travel to other
  sites within cell
• Cytoskeleton provides shape to cell and allow
  cell and its contents to be mobile
• Flagella whip-shaped tails that move some cells,
  like sperm, to other locations
• Cilia hair-like projections located on outer
  surface of some cells move particles using
  wavelike motion

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Pathology Connection Organelle Disorders

• Lysosomal storage disorder
• Occur when lysosomes missing one of their enzymes
• Results in some molecules not breaking down and
  accumulating in cells
• Many kinds of lysosomal storage disorders
• All are genetic
• Most lack effective therapies

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Pathology Connection Tay Sachs Disease

• Enzyme missing in lysosomes of nervous system
  cells
• As result, glycoproteins accumulate in cells in
  nervous system
• Build up causes inflammation and eventual
  cellular destruction
• Symptoms include mental regression, dementia and
  paralysis appearing within first year of
  patients life
• Found mostly in Ashkenazi Jews German Jews

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Tay Sachs cont

• Diagnosis appearance of cherry red spot on back
  of patients eyes abnormalities in startle
  reflex
• No treatment disease generally fatal within two
  or three years of onset
• Availability of genetic test has decreased
  incidence in recent years

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Pathology ConnectionCigarettes and paralyzed
cilia

• Smoking causes cilia in respiratory tract to
  become paralyzed
• As a result, cannot keep lungs clean
• Over time, can lead to chronic obstructive
  pulmonary disease (COPD) and other
  smoking-related lung problems
• Passive smoking (second hand smoke exposure) also
  increases risk of lung problems

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Enzymes

• Facilitate important chemical reactions in body
• One way is by speeding up reactions
• Not used up by reactions that they facilitate
  instead, act like carrier molecules
• Very specific each only facilitates (catalyzes)
  certain reactions

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Pathology Connection Phenylketonuria (PKU)

• Genetic condition enzyme disorder
• Most common in Caucasians of Irish, Scottish, or
  Scandinavian descent
• Patients missing enzyme phenylalanine
  hydroxylase
• Without enzyme, amino acid phenylalanine builds
  up in cells
• Build up affects nervous system causes
  progressive mental retardation if not treated

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Phenylketonuria (PKU) cont

• Other signs include
• Light pigmentation of skin, hair and eyes
• Abnormalities of posture and gait
• Epilepsy
• Diagnosis
• Blood tests genetic tests
• Every newborn in US routinely screened

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Phenylketonuria (PKU) cont

• Treatment low phenylalanine diet includes
  avoidance of high protein foods and products
  sweetened with aspartame (NutraSweet)
• Consequences of going off diet
• Children cognitive defects
• Adults depression, anxiety, or other
  neurological changes

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Pathology Connection Cancer

• When body is healthy, cells grow in orderly
  fashion control system prevents cells from
  reproducing too fast
• Sometimes conditions are altered that trigger
  changes in way cells reproduce this wild,
  uncontrolled reproduction can lead to too many
  cells being produced, creating a lump, or tumor
• Tumors can generally be either benign or
  malignant !!!

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Cancer cont

• Benign tumors
• Slow growth
• Tend to push healthy cells out of the way
• Generally nonlife threatening
• Malignant tumors
• Rapid growth
• Tend to invade healthy tissues
• Can enter blood or lymphatic system and start new
  tumors in other parts of body this kind of
  spread called metastasis

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Malignant Tumors
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Staging Tumors

• Prognosis often determined by stage at diagnosis
  two basic strategies for staging cancers
• Staging based on amount of metastasis
• Stage I no cancer spread
• Stage II spread to nearby tissues
• Stage III spread to the lymphatic system
• Stage IV spread to distant organs

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• Diagnosis of cancer
• Imaging techniques (MRI, CAT, X-ray, etc.)
• Blood tests
• Biopsy (surgical examination of abnormal tissue)

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Treatment of cancer

• Four main types typically 2 types of RX
• Chemotherapy uses chemicals to kill rapidly
  dividing cells
• Radiation therapy uses energy to target cancer
  cells
• Surgery removes cancer cells from body
• Biological or immunotherapy trains bodys
  natural defenses to fight cancer cells

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Microorganisms

• Four primary microorganisms
• Bacteria
• Viruses
• Fungi
• Protozoa

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Bacteria

• Bacteria can be harmful, as in case of pathogens,
  or can be harmless and essential for life
• Harmless bacteria sometimes called normal flora
• Certain bacteria in intestines help to digest
  food
• Some help to synthesize vitamin K, needed for
  blood clotting

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3 Types of Cocci Bacteria
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Viruses

• Infectious particles that have core containing
  genetic material surrounded by protective protein
  coat called a capsid
• Cannot grow, eat, or reproduce by themselves
  must enter another cell and use that cell for
  energy to grow and reproduce
• Do not respond to antibiotics can stay dormant
  in body and become active later in life

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Virus
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Fungi

• Plural form of fungus can be one-celled or
  multi-celled organism plant-like organisms with
  tiny filaments, called mycelia, that travel out
  from cell to find and then absorb nutrients
• Good fungi, like edible mushrooms, are harmless
  others can cause disease or death
• Fungi spread through release of spores
• Examples of fungal infections include athletes
  foot, thrush, or candidiasis

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Protozoa

• One-celled, animal-like organisms that can be
  found in water and soil
• Diseases caused by swallowing them or from being
  bitten by insects that carry them in their bodies
  Ex Malaria

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Types of Protozoa
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Pathology Connection How Microorganisms Cause
Disease

• Bacteria
• Destroy body tissues
• Destroy blood cells
• Inhibit ribosomes
• Cause fluid loss
• Cause high fever
• Cause decreased blood pressure
• Increase blood clotting
• Cause fluid in the lungs
• Cause paralysis

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• Signs and symptoms of bacterial infection
• High fever
• Rapid pulse
• Rapid breathing
• Abnormal, often foul-smelling discharge from
  infected area
• Pain at infection site
• Swelling at infection site

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Antibiotics

• Antibiotics used to treat bacterial infections
• Chemicals kill prokaryotic bacteria without
  harming eukaryotic cells
• Most antibiotics produced naturally by other
  microorganisms

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Fungal (Non-bacterial infections)

• Fungal infections
• Spores are inhaled
• Spores enter body through open wounds
• Spores tiny bodies resistant to environmental
  changes (able to stay dormant until conditions
  are just right)
• Most fungal spores do not cause disease in
  otherwise healthy individuals exception is
  fungal infections of skin (such as athletes foot
  and jock itch)

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Fungal infections Cont

• Many fungal infections opportunistic (only infect
  people with compromised immune systems or other
  underlying disease)
• Symptoms of fungal infection vary depending on
  location of infection
• Treatment is difficult
• Most anti-fungal drugs are highly toxic
• Many fungal infections are resistant to treatment

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Protozoan Infections

• Most protozoan infections caused by
• Ingestion of contaminated water
• Insect bites
• Many protozoans are parasites

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Protozoan Infections Cont

• Symptoms vary depending on type of protozoan
• Many are serious disease causing long term
  debilitating illness example malaria, which is
  transmitted by mosquitoes
• Some are relatively mild illnesses example
• beaver fever caused by Giardia, a
  protozoan that lives in streams and water
  supplies contaminated by fecal matter

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