Understanding cell components
• Organelles — contained in the cytoplasm and surrounded by cell membrane
• Nucleus — responsible for cellular reproduction and division and stores DNA (genetic material)
• Other cell components:
– adenosine triphosphate
– ribosomes and endoplasmic reticulum
– Golgi apparatus
– lysosomes.
– adenosine triphosphate
– ribosomes and endoplasmic reticulum
– Golgi apparatus
– lysosomes.
Stages of cell reproduction
• Stage 1 — mitosis
• Stage 2 — cytokinesis
Stages of cell division
• Prophase—chromosomes coil and shorten, the nuclear membrane dissolves, and chromatids connect to a centromere.
• Metaphase—centromeres divide, pulling the chromosomes apart, and align in the spindle.
• Anaphase—centromeres separate and pull new replicated chromosomes to the opposite sides of the cell; 46 chromosomes on each side of the cell.
• Telophase—final phase; new membrane forms around 46 chromosomes through cytokinesis producing two identical new cells.
• Prophase—chromosomes coil and shorten, the nuclear membrane dissolves, and chromatids connect to a centromere.
• Metaphase—centromeres divide, pulling the chromosomes apart, and align in the spindle.
• Anaphase—centromeres separate and pull new replicated chromosomes to the opposite sides of the cell; 46 chromosomes on each side of the cell.
• Telophase—final phase; new membrane forms around 46 chromosomes through cytokinesis producing two identical new cells.
Types of cell injury
• Toxic injury—endogenous (metabolic errors, gross malformations, hypersensitivity reactions), exogenous (alcohol, lead, carbon monoxide, drugs).
• Infectious injury—viruses, protozoa, bacteria.
• Physical injury—thermal (electrical, radiation), mechanical (trauma, surgery).
• Deficit injury—lack of basic requirement.
• Toxic injury—endogenous (metabolic errors, gross malformations, hypersensitivity reactions), exogenous (alcohol, lead, carbon monoxide, drugs).
• Infectious injury—viruses, protozoa, bacteria.
• Physical injury—thermal (electrical, radiation), mechanical (trauma, surgery).
• Deficit injury—lack of basic requirement.
Maintaining homeostasis
• Medulla, pituitary gland, reticular formation are regulators.
• Two types of feedback mechanisms maintain homeostasis:
– negative mechanism senses change and returns it to normal
– positive mechanism exaggerates change.
• Medulla, pituitary gland, reticular formation are regulators.
• Two types of feedback mechanisms maintain homeostasis:
– negative mechanism senses change and returns it to normal
– positive mechanism exaggerates change.
Differentiating disease and illness
Disease
• Occurs when homeostasis isn’t maintained.
• Influenced by genetic factors, unhealthy behaviors, personality type, and perception of the disease.
• Manifests in various ways depending on patient’s environment.
• Occurs when homeostasis isn’t maintained.
• Influenced by genetic factors, unhealthy behaviors, personality type, and perception of the disease.
• Manifests in various ways depending on patient’s environment.
Illness
• Occurs when a person is no longer in a state of “normal” health.
• Enables a person’s body to adapt to the disease.
• Occurs when a person is no longer in a state of “normal” health.
• Enables a person’s body to adapt to the disease.
Causes of disease
• Intrinsic—hereditary traits, age, gender
• Extrinsic—infectious agents or behaviors, such as:
– inactivity
– smoking
– using drugs.
• Stressors, such as:
– physiologic
– psychologic.
• Intrinsic—hereditary traits, age, gender
• Extrinsic—infectious agents or behaviors, such as:
– inactivity
– smoking
– using drugs.
• Stressors, such as:
– physiologic
– psychologic.
How diseases develop
Signs and symptoms
• Increase or decrease in metabolism or cell division
• Hypofunction such as constipation
• Hyperfunction such as increased mucus production
• Increased mechanical function such as a seizure.
• Increase or decrease in metabolism or cell division
• Hypofunction such as constipation
• Hyperfunction such as increased mucus production
• Increased mechanical function such as a seizure.
Stages of disease
• Exposure or injury
• Latent or incubation period
• Prodromal period
• Acute phase
• Remission
• Convalescence
• Recovery
• Exposure or injury
• Latent or incubation period
• Prodromal period
• Acute phase
• Remission
• Convalescence
• Recovery
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