unit 1.2 - cellular pathophysiology

cellular pathology

• refers to the study of abnormalities or changes that occur at the cellular level in various diseases or conditions

• examining the structure, function, and behavior of cells to understand the underlying mechanisms of disease development

• crucial in diagnosing and treating diseases, as it provides insights into the specific cellular alterations that contribute to the disease process

oxygen, waste removal, water, nutrients

normal requirements for cell function

epithelial tissue

• covers the surface of organs and line body cavities

• protective barrier and helps with absorption, secretion, and sensory reception

connective tissue

• provides support and structure to the body

• ex. bone, cartilage, adipose (fat), and blood

• also plays a role in immunity and the transportation of nutrients and waste

muscle tissue

responsible for movement in the body

skeletal muscle

responsible for the movement of the body

smooth muscle

involuntary movement in organs (peristalsis, bladder)

cardiac muscle

the contraction of the heart

nervous tissue

• involves in transmitting and processing information in the body

• enables sensory perception, motor control, and cognitive functions

dna damage, oxidative stress, mitochondrial dysfunction, protein misfolding, cellular senescence, autophagy dysfunction

common cellular dysfunctions

dna damage

leads to errors in cell division or growth

oxidative stress

exposed to stress causing free radicals or harmful molecules (ex. ROS)

antioxidants

help fight the ROS

mitochondrial dysfunction

if it’s not functioning properly, there is reduced energy, ATP, reduced activity = the cell wouldn’t function well

protein misfolding

prevent the protein from functioning properly

cellular senescence

occurs when the cells stops dividing (cell division)

autophagy dysfunction

when the cells cannot get properly removed or recycled ; the normal biological process where cells clean, repair, and recycle their own damaged parts has broken down or stopped working correctly

aging, development, functions

cellular dysfunction contributes to ____, disease ______, and impaired tissue _____

genetic factors, environmental factors

causes and mechanisms of cellular dysfunction

genetic factors

affects how cell function, grow, and respond to stress

• gene mutations

• genetic predisposition

• inherited genetic disorders

environmental factors

surroundings and lifestyles, can increase the risk for diseases overtime

• exposure to toxins

• pollution

• stress

adaptation

reversible, structural, and functional response to physiology or pathologic conditins

cell adaptation or cell death

severe or long term stressors can lead to

atrophy, hypertrophy, hyperplasia, (hypertrophy and hyperplasia), metaplasia

five ways cells adapt to their environment and stressors: cope with demand or stressors

hormonal hyperplasia

occurs with estrogen dependent organs (uterus, breast)

pathologic hyperplasia

abnormal proliferation from excessive hormonal stimulation (endometrium and prostate) - increase the risk of cancer

atrophy

decrease in cell size and function

hypertrophy

increase in cell size and function

hyperplasia

increase in cell number

metaplasia

change in cell type, an adaptive response to the environment

apoptosis

programmed cell death

dysplasia

• abnormal growth or development of cells or tissues within an organ or tissue

• it is characterized by changes in the size, shape, and organization of cells, which can lead to the loss of normal tissue architecture and function

• the context of cancer, dysplasia is often considered a pre-cancerous condition

severe dysplasia

being more likely to progress to cancer

anaplasia

loss of differentiation resulting cells that are undifferentiated or poorly differentiated ; does not resemble the normal or original cell

neoplasia

abnormal or uncontrolled cell growth, leading to the formation of a mass or tumour

carcinoma in situ

a type of cancer that has not invaded the surrounding tissue

common biochemical themes in cell injury and cell death

• loss of cell membrane integrity

• disruption of intracellular calcium homeostasis

• mitochondrial dysfunction (produced the cell energy — can damage the organelles = damage the cell)

loss of membrane integrity

• cell membrane rupture due to physical trauma

• disruption of cell membrane by toxins or chemicals

• increase in reactive oxygen species (ROS) production

• activation of inflammatory response

• alteration of intracellular signalling pathways

disruption of intracellular calcium homeostasis

• excessive influx of calcium ions into the cell – abnormal (there should only be enough inside the cell)

• impaired functioning of calcium ion channels

mitochondrial dysfunction

• impaired oxidative phosphorylation

• decreased ATP production

increase in ROS production

• excessive generation of free radicals

• failure of antioxidant defense mechanisms

activation of inflammatory pathways

• release of pro-inflammatory cytokines

• infiltration of immune cells

alteration of intracellular signalling pathways

• dysregulation of cell signalling molecules

• activation of pro-apoptotic signalling pathways

cellular injury

hypoxia, chemicals, free radicals, infectious agents, physical and mechanical factors, chemicals, immunological reactions, genetic factors, nutritional imbalances

hypoxic cellular injury

refers to damage cells caused by lack of oxygen

results in ischemia

intracellular accumulations

fat, cholesterol, protein, glycogens, pigments

fat

• accumulate in liver of chronic alcoholic d/t cells unable to metabolize triglycerides

examples: fatty liver

cholesterol

in arterial cell walls e.g. atherosclerosis  (formation of plaque)

protein

abnormal proteins collect in variety of disease e.g. liver disease d/t ETOH  (alcohol), genetic abnormalities, etc.)

glycogens

diabetes mellitus (glucose metabolism is disrupted)

pigments

melanin in skin with sun exposure (too much production of melanin)

cell swelling, disrupted cellular function, tissue damage

effects of water accumulation in cells

cell swelling

H2o accumulates inside the cells, causing them to swell and increase size

disrupted cellular functions

the excess h2o can disrupt normal cellular process, leading to impaired function

tissue damage

prolonged h2o accumulation can result in tissue damage and dysfunction

apoptosis, necrosis

cell death

apoptosis

cellular suicide (normal programming of the cells)

necrosis

death of cells related to cell injury (uncontrolled cell death, hypoxia, infection, toxins, trauma) ; can trigger inflammatory responses in the body

reactive oxygen species

• refer to highly reactive molecules that are formed as byproducts of normal cellular metabolism

• they include molecules like superoxide, hydrogen peroxide, and hydroxyl radicals

• excessive production and inadequate antioxidant defenses can lead to oxidative stress

tissue necrosis

• refers to the death of cells or tissues in the body

• occurs when there is disruption in the blood supply or due to various pathological factors

• can result in the loss of normal tissue structure and function

• rapid loss of plasma membrane, swelling of organelles & dysfunction of mitochondria

• ___ cells leak contents and inflammation in surrounding tissue occurs

• can be caused by factors such as injury, infection, ischemia, toxins, or underlying medical condition

coagulative, liquefactive, caseous, fat, gangrenous

five types of tissue necrosis

type 1: coagulative necrosis

the affected tissue becomes firm and pale due to protein denaturation, severe ischemia (myocardial infarction)

type 2: liquefactive necrosis

characterized by the formation of liquid-filled spaces within the affected tissue, cell digested by other cells; liquefies forming cysts (brain abscess)

type 3: caseous necrosis

leads to the formation of cheese-like, granular, tissue texture

type 4: fat necrosis

the adipose tissue is broken down, resulting in the release of fatty acids, tissue appears opaque and chalk-white (pancreatitis)

type 5: gangrenous necrosis

occurs when a large area of tissue undergoes necrosis due to compromised blood supply (dry gangrene in diabetes)

caloric restriction and intermittent fasting, physical exercise, pharmacological interventions, stem cell therapies

potential therapeutic intervention for aging and altered cellular biology