Questions and Answers
What is the primary function of the sodium/potassium pump in cellular transport?
Which of the following types of cellular receptors is directly linked to an ion channel?
What is the primary mechanism by which cells maintain homeostasis?
Which type of cellular communication involves the release of chemical messengers that bind to receptors on adjacent cells?
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What is the primary function of the extracellular matrix?
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How do cells respond to changes in their environment?
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What is the primary function of the basement membrane?
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Which type of cellular adaptation involves changes in the structure or function of cellular components?
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What is the primary difference between water soluble and lipid soluble chemical messengers in a signal transduction pathway?
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What is the primary function of negative feedback loops in the regulation of hormone secretion?
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What is the term for the process by which the body adjusts its sensitivity to the concentration of a signaling hormone?
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What is the term for the movement of water from an area of high concentration to an area of low concentration?
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What is the term for the pressure exerted by solutes in a solution?
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What is the primary cause of edema?
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What is the primary function of the lymphatic system in maintaining water balance?
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What is the relationship between sodium, potassium, chloride, and bicarbonate in maintaining the osmotic balance of the extracellular environment?
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What is the term for the ability of a genetic trait to be expressed despite not being fully penetrant?
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What is the primary mechanism by which the carbonic acid-bicarbonate buffer system maintains pH homeostasis?
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What type of epigenetic modification involves the addition of a methyl group to the cytosine residue in DNA?
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What is the term for the ability of cells to adapt to changes in their environment through reversible changes in cellular structure or function?
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What is the term for the deficiency of magnesium in the body?
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What is the term for the process by which cells die due to a lack of oxygen?
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What is the term for the study of heritable changes in gene function that occur without a change in the underlying DNA sequence?
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What is the term for the ability of a gene to be expressed in a particular individual, but not in others, despite having the same genotype?
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Study Notes
The Cell Membrane, Transport, and Cellular Adhesion
- Homeostasis is the maintenance of a stable internal environment despite changes in the external environment, and it's essential for the normal functioning of the human body.
- The cell membrane is composed of phospholipids and proteins, and their distribution influences membrane permeability to ions, hydrophilic, and hydrophobic compounds.
- Transport mechanisms across the cell membrane include:
- Passive transport: diffusion, facilitated diffusion, osmosis
- Active transport: uses energy to move solutes against a gradient, e.g., sodium/potassium pump
- The sodium/potassium pump uses energy from Na+ and K+ electrochemical gradients to drive the net movement of other solutes, such as Na+/glucose co-transport and Na+/Ca2+ exchange or counter-transport.
- Mechanisms that bind cells together include:
- Extracellular matrix
- Basement membrane
- Cell adhesion molecules
- Specialized cell junctions
Mechanisms of Cellular Communication and Signal Transduction
- A chemical/cellular messenger is a molecule that transmits a signal from one cell to another.
- Cellular receptors have specific characteristics and play a crucial role in cellular communication.
- Cells communicate through:
- Contact-dependent mechanisms
- Hormonal mechanisms
- Paracrine mechanisms
- Autocrine mechanisms
- Neurohormonal and neurotransmitter mechanisms
- Solubility of a chemical messenger influences its transport and mechanism of communication with a cell.
- There are three classes of plasma membrane receptors:
- Channel-linked receptors
- Catalytic receptors
- G-protein-linked receptors
- Signal transduction pathways involve:
- Binding of a chemical messenger to a receptor
- Activation of a signaling cascade
- Response to the signal
- Regulation of hormone secretion occurs through positive-feedback and negative-feedback loops.
Sodium, Chloride, and Water Balance
- Total body water (TBW) is divided into:
- Intracellular fluid (ICF)
- Extracellular fluid (ECF)
- Interstitial fluid
- Blood plasma
- TBW decreases with age.
- Osmosis is the movement of water from a higher to a lower solute concentration.
- Osmolality, osmolality, tonicity, osmotic pressure, and oncotic pressure are important concepts in understanding water balance.
- Water movement across bodily fluid compartments is driven by solute concentration, affecting cell volume in iso-tonic, hyper-tonic, and hypo-tonic solutions.
- Forces controlling fluid movement across the capillary wall include:
- Capillary hydrostatic pressure
- Interstitial oncotic pressure
- Capillary oncotic pressure
- Interstitial hydrostatic pressure
- Edema develops due to:
- Decreased capillary oncotic pressure
- Increased capillary permeability
- Increased capillary hydrostatic pressure
- Lymphatic obstruction
- Electrolyte distribution:
- Intracellular fluid: high in K+, low in Na+
- Extracellular fluid: high in Na+, low in K+
- Sodium, potassium, chloride, and bicarbonate maintain osmotic balance in the extracellular environment.
Acid-Base Balance
- Physiologic buffering systems maintain pH homeostasis.
- Le Chatelier's principle applies to alterations in the carbonic acid-bicarbonate buffer.
Mechanisms of Inheritance
- Genetic terms include:
- Dominance
- Recessiveness
- Incomplete dominance
- Codominance
- Polygenic inheritance
- Inheritance patterns include:
- Autosomal dominant
- Autosomal recessive
- X-linked dominant
- X-linked recessive
- Mitochondrial inheritance
- Penetrance and expressivity describe the degree to which a genotype is expressed phenotypically.
- DNA mutations can cause diseases, and their outcomes depend on the type of mutation.
- Epigenetics involves:
- DNA methylation
- Histone modification
- Chromatin remodeling
- Epigenetic modifications influence gene expression and disease development.
Cellular Adaptation, Injury, and Death
- Cellular adaptations include:
- Hypertrophy
- Hyperplasia
- Atrophy
- Metaplasia
- Dysplasia
- Cell injury and death can occur due to:
- ATP depletion
- Reactive oxygen species
- Calcium entry
- Mitochondrial damage
- Membrane damage
- Protein misfolding
- DNA damage
- Reversible cell injury can progress to irreversible cell injury and death.
- Mechanisms of cell injury include:
- Ischemia and hypoxia
- Ischemia-reperfusion
- Free radicals and reactive oxygen species
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Description
Understand the importance of homeostasis, cell membrane composition, and transport mechanisms in the human body. Learn about phospholipids and proteins' influence on membrane permeability.
