Cells

Cells are the smallest functional unit of life

Cells Function

can self-reproduce and transmit genetic info

• Movement
• Conductivity
• Metabolic absorption
• Secretion
• Excretion
• Respiration
• Reproduction
• Communication

At what level do disease start/attack ?

cellular level

3 basic parts to a cell

• Plasma membrane
• Nucleus
• Cytoplasm

What is the Cell membrane (aka plasma membrane)

Provide the selective transport system

plasma membrane also has an important role in cell-to-cell

recognition, cellular mobility, and the maintenance of cellular shape

Semipermeable structure that separates intracellular from extracellular environment

It lets in certain extracellular fluids into the cells, it takes part in electrical current conduction (ex. Na action potential), and hormone receptors bind to it.

What is the cell membrane composition

Phospholipid bilayer makes up the semi-permeable membrane which has a water soluble head (hydrophilic) and water-Insoluble tail (hydrophobic)

It is made of an arranged mixture of lipids, proteins, and carbohydrates

Functions of Cell Membrane Proteins

What is the Nucleus

largest membrane bound organelle

Control center of the cell

Responsible for cell division and control of genetic information,

The nucleus contains the nucleolus: where DNA is stored in Eukaryotes

Cytoplasm

the fluid filling

contains membrane enclosed organelles and a variety of ions (ex. Na+), lipids, and proteins

functions of organelles within the cytoplasm:

Functions of organelles can be divided into four major categories:

(1) genetic control

(2) manufacturing, distributing, and breaking
down molecules

(3) energy processing

(4) structural support, movement, and communication between cells.

Ribosomes:

where proteins are synthesized(produced)

cell's “protein factories.”

RNA-protein complexes that use the information from DNA, written in messenger
RNA (mRNA), to build proteins and provide sites for cellular protein synthesis

Endoplasmic Reticulum

rough ER—site of protein synthesis

smooth ER—site of lipid synthesis

Rough ER:

rough endoplasmic reticulum (RER)
specializes in the synthesis, folding, and transport of protein components

Proteins are produced at attached ribosomes, but move through inside of rER and are chemically modified by enzymes

Smooth ER

synthesis of steroid hormones and is responsible
for a variety of reactions required to remove toxic substances from the cell.

Contains enzymes used in lipid synthesis. In muscle cells, holds and releases when signaled Ca2+ ions. In liver cells, detoxify many different drugs.

Golgi apparatus

" the post office"

modifies and packages secretory granules and vesicles

responsible for processing and packaging proteins into secretory
vesicles that break away from the Golgi complex and migrate to a variety of intracellular and extracellular destinations, including the plasma membrane.

Peroxisomes

• Detoxify compounds and fatty acids
• Use oxygen to remove hydrogen atoms from substrates
• Synthesize specialized phospholipids for nerve cell myelination

Mitochrondria

"power house"

responsible for cellular respiration and energy production

most energy in the form of ATP is made here

• contain the metabolic machinery necessary for cellular energy metabolism
• enzymes of the respiratory chain (electron transport chain), found in the inner membrane of the
  mitochondria, generate most of the cell's adenosine triphosphate (ATP)

Lysosomes

"digestive organelles" "Lysol"

Intracellular digestion system

phagocytosis of unwanted material in the cell

• sac-like structures that contain digestive enzymes
• enzymes are responsible for digesting most cellular substances to their basic form, such as amino acids, fatty acids, and carbohydrates (sugars)
• Cellular injury leads to a release of the lysosomal enzymes, causing
  cellular self-digestion
• serve as signaling hubs in a network for cellular adaptation

Cytoskeleton

microtubules, microfilaments, and intermediate filaments make up the cytoskeleton and control the shape and movement

Maintains the cell’s shape and internal organization

• “bone and muscle” of the cell
• internal skeleton is composed of a network of protein filaments, including microtubules and actin filaments (microfilaments).
• form cell extensions (microvilli, cilia, flagella).

Tissues

• Muscle
• Neural
• Epithelial
• Connective

Cellular Adaptations

When the internal environment changes, cells adapt to survive

3 general ways a cell adapts: Change in size, number, type

• Atrophy—decrease in cell size
• Hypertrophy—increase in cell size
• Hyperplasia—increase in cell number
• Metaplasia—reversible replacement of one differentiated cell type by another cell type
• Dysplasia—or deranged cellular growth, is not considered a true cellular adaptation but rather
atypical hyperplasia

Atrophy

decrease in cell size

• A Smaller cell size with decreased mass (which improves its efficiency and allows the cell to survive)

• Occurs when there are poor environmental conditions
• Causes:
• Lack of use
• Denervation (nerves not stimulating area)
• Loss of endocrine stimulation
• Poor nutrition
• Decreased blood flow (ischemia)

Hypertrophy

increase in cell size

• Increased cell size with increased tissue mass
• Occurs when there is increased workload on an organ/body part
• Typically seen in cardiac or skeletal muscle
• Can occur in normal physiology (ex. lots of exercise causes muscle hypertrophy "runner heart"), but it is usually pathologic to adapt to stress on the organ
• Ex. Myocardial hypertrophy from hypertension

Hyperplasia

increase in cell #

• Increased number of cells which results in increased tissue muscle mass
• Two General Causes:
• Physiologic: due to expected estrogen hormones (ex. breast and uterine growth during pregnancy)
• Non-physiologic: due to excess hormones (ex. benign prostatic hyperplasia in older men due to too much androgens)
• While hyperplasia and hypertrophy are distinctly different, they typically occur together

Metaplasia

reversible replacement of one differentiated cell type by another cell type

• Occurs when one cell type is replaced by another
• But must be same cell type (ex. epithelial cell for different type of epithelial cell)
• Occurs in response to chronic inflammation/irritation to better adapt to the situation
• Ex: Bronchus of a chronic smoker changes the epithelium from normal columnar to squamous

Dysplasia

deranged cellular growth, is not considered a true cellular adaptation but rather atypical hyperplasia (inc # of cells)

• Dysplasia refers to abnormal changes in the size, shape, and organization of mature cells
• dysplasia does not refer to cancer
• Dysplastic changes are common in the epithelial tissue of the uterine cervix, the endometrium, and the gastrointestinal (GI) and respiratory tract mucosa
• Dysplasia is described as “low grade” or “high grade,”

What is cell injury?

• Leads to injury of tissues and organs, determining structural patterns of disease
• Injured cells may recover (reversible injury) or die (irreversible injury)
• Causes cell stress
• Is acute or chronic and reversible or irreversible

Causes of cell injury

• Lack of oxygen (hypoxia)
• Free radicals
• Toxic chemicals
• Infectious agents
• Physical and mechanical factors
• Immunologic reactions
• Genetic factors
• Nutritional imbalances
• Physical trauma

What happens in Lack of Oxygen Cell Injury

• Ischemia-induced reduction in ATP levels causes a failure of the plasma membrane's sodium– potassium (Na+-K+) pump and sodium–calcium (Na+-Ca++) exchange mechanisms.

• Sodium and calcium influx into and accumulate in the cell. Potassium (K+) diffuses out of the cell. Without the pump mechanism, sodium and water can freely enter the cell resulting in cellular swelling and dilation of the ER.

What are different types of Toxic Chemicals

Carbon Monoxide

Lead

Mercury

ETOH

Street Drugs

What are characteristics of carbon monoxide?

Where is it found?

Consequences of CO poisonings?

Odorless and colorless

• Sources: emitted during combustion processes, defective furnaces, occupation exposure (coal mining, firefighting, welding, engine repair), or exposure to tobacco smoke (first or secondhand)

• Produces hypoxic injury
• Directly reduces the oxygen-carrying capacity of blood, and promotes tissue hypoxia
• Causes reduction of oxygen delivery to organs, such as the heart and brain, by binding to hemoglobin (carboxyhemoglobin) reducing the blood’s oxygen-carrying capacity
• CO for hemoglobin is 300 times greater than that of
  oxygen, CO quickly binds with hemoglobin, preventing oxygen molecules from binding to hemoglobin,
  and they are thus transported to tissues.

Lead Poisoning

Where is it found?

Consequences of LP?

older homes, found in hazardous concentrations in food, water, and air

central and peripheral nervous systems

increasing their risks for damage to the brain and nervous system, slowed growth and development, learning and behavior problems (e.g.,
reduced IQ, attention-deficit/hyperactivity disorder [ADHD], juvenile delinquency, and criminal behavior), and hearing and speech problems

Street Drugs

Most popular and dangerous drugs include opioids, methamphetamine (“meth”), marijuana, cocaine, and heroin

Carbon tetrachloride, alcohol, and social
drugs can significantly alter cellular function and injure cellular structures.

10 drugs most frequently involved in overdose deaths include heroin,
oxycodone, methadone, morphine, hydrocodone, and fentanyl; the benzodiazepines alprazolam and
diazepam; and the stimulants cocaine and methamphetamine

Mercury

Sources?

Who should avoid eating Mercury items?

• Two major sources are fish and healthcare equipment
• Recommendation: Pregnant women, nursing mothers, and young children should avoid eating fish with a high mercury content

found in dental amalgam; some vaccine preservatives; food products (e.g., rice); and terrestrial and marine animals, some of which are consumed by humans.

Lipid solubility of methylmercury and metallic mercury increases their accumulation in the brain, altering neuromotor, cognitive, and behavioral functions

avoid eating fish with a high mercury content (>1 part per million [ppm]), such as shark, swordfish, tile fish, and king mackerel.

lower in methylmercury include shrimp, canned light tuna, salmon, pollock, and catfish

ETOH

What deficiencies does it cause; S/S?

Consequences of ETOH

• Results in major nutritional deficiencies, especially folate
• Is metabolized in the liver
• Has a protective effect with the cardiovascular system,
  up to a point
• Acute alcoholism affects the central nervous system (CNS)
• Chronic alcoholism affects primarily the liver and stomach
• Alcohol-induced liver disease (fatty liver, alcoholic hepatitis, cirrhosis)
• Acute gastritis- affects lining of the stomach
• Can cause fetal alcohol syndrome

Fetal Alcoholism Features

short palpebral fissure length, smooth philtrum, and thin upper lip.

Unitntentional Injuries

• Unintentional and intentional injury
• Falls, motor vehicle injuries, opioid overdose, poisonings
• Sports- and recreation-related injuries in children
• Firearms
• Medical care- injuries in hospital, falls
• Suicide
• Examples of hospital-acquired
  conditions include adverse drug events, catheter-associated urinary tract infections, central-lineassociated bloodstream infections, pressure injuries, and surgical site infections, among others

Asphixial Injuries

• Cause: Failure of cells to receive or use oxygen
• Suffocation: the process of dying as a result of lack of oxygen, can result from either a lack of oxygen in the environment or from a blockage of the respiratory airways
  • Choking suffocations: obstruction of the pulmonary airways. An object may
    become lodged in a large airway, directly obstructing breathing. Injury or disease also may result from
    soft tissue swelling surrounding the airway, leading to a partial or complete obstruction and subsequent
    asphyxiation.
  • Compression suffication: mechanical compression of the chest or abdomen prevents normal respiratory movements
• Strangulation: compression of the blood vessels and air passages resulting from external pressure on the neck.
• Hanging: noose or similar object is placed around the neck; V shaped mark on neck
• Ligature: some form of cord encircles and tightens about the neck; horizontal mark on neck
• Manual: assailant's hands compress the neck of the victim to the point
  where death by asphyxiation occurs
• Chemical asphyxiants: prevent O2 or block O2 utilization
• Drowning: death from inhalation of and suffocation by a liquid, usually water

Infection Injuries

• Pathogenicity (virulence) of a microorganism
• Disease-producing potential
• Invasion and destruction
• Toxin production
• Production of hypersensitivity reactions

• Examples include:
• Bacteria
• Viruses
• Fungi

(1) invade and destroy cells,

(2) produce toxins

(3) produce damaging hypersensitivity reactions

Nutritional Injuries

Funtions?

Examples of Excessive and Deficient

• Essential nutrients are required for cells to function normally (Imbalances in nutrition can cause altered cellular structure and function.)
• Proteins, carbohydrates, lipids, vitamins, and minerals)
• Micronutrients and macronutrients
• Examples:
• Deficient intake
  • Iron deficient= iron deficiency anemia
  • B12 deficiency= neuropathy or memory loss
• Excessive intake
  
  • High fat in diet= may lead to atherosclerosis of arteries
  • Deficient nutrition:

Temperature Injuries

• Hypothermic injury
• Slows cellular metabolic processes
• Produces reactive oxygen species
• Hyperthermic injury
• Heat cramps, heat exhaustion, heat stroke

• Malignant hyperthermia
• Neuroleptic malignant syndrome

• Drug-induced hyperthermia
• Burns

Atompsphere Pressure Injuries

• Decompression sickness or caisson disease

• “The bends,” diver disease- can cause embolism or strokes

• High-altitude illness
• High-altitude pulmonary edema (HAPE)
• can take Diomox to prevent
• High-altitude cerebral edema (HACE)
• Acute mountain sickness (AMS)

Apotosis

• No inflammatory changes

• Type I—programmed cell death
• Type II—autophagic cell death

Necrosis

• Includes inflammatory changes
• Autolysis

Necrosis is a form of cell destruction characterized by ruptured plasma and lysosomal membrane structures, denaturation of cellular proteins, leakage of cellular contents, rapid loss of ATP, swelling of organelles, severe mitochondrial damage, and local inflammation

Types of Gangrene

• Dry gangrene: lack of arterial blood supply, but venous flow can carry fluid out of tissue.
• Dry, shrinks, skin wrinkles, dark brown/black, usually affects the extremities
• Wet gangrene: lack of venous flow lets fluid accumulate in tissue.
• Cold, swollen, pulseless, moist, black, foul odor due to bacteria, may affect extremities or internal organs
• Gas gangrene: Clostridium infection.
• Hydrogen sulfide bubbles in muscle.
• Crepitus is sensation of bubbles that can be felt underneath the skin.

Cellular Aging

• Even without disease, starting at age 40, there is progressive decline in our body.
• Decreased muscle strength, nerve conduction speed, cardiac reserve, etc.

υThought to be due to individual cell function decline with age, particularly in the mitochondria

• Theories of Aging:
• Pre-programmed theories=age changes are genetically programmed
• Damage (error) theories= age changes are due to many random events over time which ultimately cause DNA damage