Foundations of Pathophysiology – Cells in Health & Disease

48 flashcards covering major concepts from cell structure, organelles, functions, adaptation, injury mechanisms, necrosis, apoptosis, oxidative stress, aging, and systemic manifestations.

According to Claude Bernard, why must physiological qualities always be considered in relation to the whole organism?

Because the value and true significance of any physiological quality can only be understood by its effects on the entire organism, not in isolated parts.

What evolutionary advancement increased the efficiency and independence of living organisms from unicellular to multicellular life?

The development of specialized cells forming tissues and organs, accompanied by complex internal infrastructure.

Which cellular structure houses DNA, controls genetic information, and directs cell division?

The nucleus.

What is the primary energy-producing process of mitochondria called?

Oxidative phosphorylation (electron-transport chain).

Name two roles of the plasma membrane besides controlling the internal composition of the cell.

Cell-to-cell recognition and maintenance of cellular shape and mobility.

Which organelle is responsible for protein synthesis within the cytoplasm?

Ribosomes.

What are the smooth and rough endoplasmic reticulum (ER) primarily specialized for?

Synthesis, folding, and transport of proteins and lipids; the rough ER has ribosomes attached for protein synthesis.

Which organelle processes and packages proteins into secretory vesicles?

The Golgi complex.

What cellular ‘bone and muscle’ provides structural support and forms cell extensions like cilia and flagella?

The cytoskeleton.

Which enzyme-filled organelle digests cellular debris and can trigger self-destruction after injury?

Lysosomes.

What type of enzymes do peroxisomes contain and what harmful by-product do they form?

Oxidative enzymes such as catalase and urate oxidase; they form hydrogen peroxide.

List the eight basic functions common to most cells.

Movement, conductivity, metabolic absorption, secretion, excretion, respiration, reproduction, and communication.

Define homeostasis in a physiologic context.

The process by which biological systems maintain internal stability while adjusting to external changes.

What is cellular adaptation and why does it occur?

Reversible structural or functional changes allowing cells to survive environmental stress and avoid injury.

Differentiate atrophy, hypertrophy, and hyperplasia.

Atrophy: decreased cell size; Hypertrophy: increased cell size; Hyperplasia: increased cell number.

What is metaplasia?

Reversible replacement of one mature cell type by another, often less specialized, cell type.

Why is dysplasia not considered a true adaptive response?

Because it represents disordered, atypical cell growth often preceding malignancy rather than a controlled adaptation.

Give an example of physiologic hypertrophy.

Left ventricular muscle enlargement in response to increased workload (e.g., exercise or hypertension).

What imaging hallmark signifies cerebral atrophy?

Ventricular enlargement, cortical thinning, and hippocampal volume loss on longitudinal scans.

Define reversible versus irreversible cellular injury.

Reversible injury allows cellular recovery when stress is removed; irreversible injury leads to cell death.

List at least four major categories of etiologic factors that can cause cellular injury.

Hypoxia/ischemia, chemical (toxic) agents, infectious agents, physical/mechanical factors, immunologic reactions, genetic factors, nutritional imbalances, free radicals.

Why is hypoxia considered the most common cause of cellular injury?

Because insufficient oxygen impairs ATP production in mitochondria, affecting essential cellular processes.

What paradoxical injury can accompany restoration of blood flow to ischemic tissue?

Ischemia-reperfusion (reoxygenation) injury.

Explain oxidative stress.

Cellular damage caused by an imbalance between reactive oxygen species (ROS) production and antioxidant defenses.

Give two examples of asphyxial injury types.

Suffocation and strangulation (others: chemical asphyxiants, drowning).

How can immune and inflammatory responses cause cellular membrane injury?

Through direct contact by immune cells and release of biochemical mediators like histamine, complement proteins, and proteases.

Name the two broad categories of substances that accumulate in cells during infiltrations.

Normal cellular substances (water, lipids, proteins, carbohydrates) and abnormal substances (endogenous or exogenous).

What are the four mechanisms leading to intracellular accumulations?

1) Inadequate removal of normal substance, 2) accumulation of abnormal substance due to folding/transport defects, 3) failure to degrade endogenous substance (enzyme deficiency), 4) deposition of exogenous materials.

Which plasma enzyme elevation commonly indicates skeletal muscle injury?

Creatine kinase (CK).

Describe the sequence from normal cell to cell death when stress is applied and exceeds adaptation.

Normal cell → adaptation → reversible injury (if stress persists) → irreversible injury → cell death.

What is necrosis?

Sum of morphological changes after cell death characterized by uncontrolled digestion of cell components and inflammation.

List the five major morphologic types of necrosis.

Coagulative, liquefactive, caseous, fat, and gangrenous necrosis.

Define apoptosis.

Programmed, energy-dependent cell death that eliminates unwanted cells without provoking inflammation.

Give two pathologic situations where apoptosis is implicated.

Accumulation of misfolded proteins in neurodegenerative diseases and cytotoxic T cell killing of virus-infected cells.

How does the cell cycle checkpoint at G1/S contribute to pathophysiology when dysregulated?

Loss of control (e.g., Rb hyper-phosphorylation) can permit uncontrolled cell proliferation and oncogenesis.

What is cellular senescence and how does it relate to aging?

Permanent cell cycle arrest in response to stress; senescent cells accumulate, contributing to tissue dysfunction during aging.

Distinguish life span from aging.

Life span is the period from birth to death; aging is the progressive, inevitable physiologic process leading to decreased homeostasis during that span.

State one conclusion from the lecture about cellular role in pathophysiology.

Cells regulate normal body structure and function; when adaptation fails, transient or permanent damage ensues, underpinning disease processes.

Which component of the cytoskeleton forms microvilli, cilia, and flagella?

Microfilaments (actin) and microtubules.

What is the role of autophagy in chronic cell injury?

A survival mechanism where cells digest their own components to recycle nutrients and remove damaged organelles.

Explain the relationship between hypoxia and ROS generation in mitochondria.

Hypoxia impairs electron transport, leading to leakage of electrons that react with oxygen to form ROS.

Why can accumulation of misfolded proteins trigger apoptosis?

Because ER stress activates signaling pathways that initiate programmed cell death when homeostasis cannot be restored.

How do lysosomal enzymes contribute to necrosis once released into the cytoplasm?

They digest cellular components, leading to autolysis and inflammatory response.

Which cell function involves generating forces that produce motion in the body?

Movement, performed primarily by muscle cells.

What systemic manifestation of cellular injury is mediated by interleukin-1 and prostaglandins?

Fever.

Name one advantage and one disadvantage of reactive oxygen species (ROS).

Advantage: regulate signaling pathways; Disadvantage: cause oxidative damage to lipids, proteins, and DNA when in excess.