Cellular Respiration Overview

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Questions and Answers

What characteristic distinguishes the nervous system from the endocrine system regarding its structural arrangement?

It has long distances of action across the body.

It is a wireless system via endocrine glands.

It relies on hormones released into the bloodstream.

It operates through anatomic relationships between neurons and target cells. (correct)

Which statement best describes the speed of reactions in the nervous system compared to the endocrine system?

Nervous system reactions are rapid, occurring in milliseconds. (correct)

Nervous system reactions are slower and take minutes to hours.

Endocrine system reactions are immediate and occur in milliseconds.

Endocrine system reactions are always immediate, regardless of the hormone.

What is a major function of the endocrine system?

To coordinate rapid, precise reactions.

To manage activities that require long duration. (correct)

To regulate homeostasis through immediate actions.

To control activities that require short duration.

Which aspect of the endocrine system focuses on the specificity of action?

It demands on target cell binding and responsiveness to hormones. Signup and view all the answers

How do the distance of action characteristics compare between the nervous and endocrine systems?

The endocrine system operates over long distances through the bloodstream. Signup and view all the answers

What happens to the membrane potential when excitatory postsynaptic potential (EPSP) occurs?

The membrane potential becomes more positive. Signup and view all the answers

Which condition must be met for an action potential (AP) to be triggered?

Membrane must meet the threshold potential of -55mV. Signup and view all the answers

What is the state of Na channels when the membrane potential peaks at 40mV?

Na channels are inactivated. Signup and view all the answers

During hyperpolarization, what voltage does the membrane typically drop to?

-75mV Signup and view all the answers

What role does the Na/K pump play in the context of action potentials?

It assists in repolarization and maintains resting potential. Signup and view all the answers

What is the primary role of the Na/K pump in maintaining resting membrane potential?

It maintains the concentration gradient of potassium and sodium ions. Signup and view all the answers

During an action potential, what occurs first when a neurotransmitter binds to dendrites?

Sodium channels open, allowing Na+ to enter the cell. Signup and view all the answers

What determines the equilibrium potential for an ion according to the Nernst Equation?

The cell's permeability to the ion and its concentration gradient. Signup and view all the answers

Which ion movement primarily contributes to the resting membrane potential of approximately -65mV?

Potassium ions moving out of the cell. Signup and view all the answers

What happens to chloride ions during the establishment of the resting membrane potential?

They leak freely into the cell, lowering the membrane potential. Signup and view all the answers

Which statement accurately describes the behavior of calcium ions during resting membrane potential?

A small amount of calcium enters the cell due to the concentration gradient. Signup and view all the answers

The equilibrium potential for potassium ions ($K^+$) is approximately -92mV. What does this value indicate about the net movement of potassium ions?

Potassium ions are generally moving out of the neuron. Signup and view all the answers

What role do K+ leak channels play in the resting membrane potential?

They allow K+ ions to move freely out of the cell based on concentration gradients. Signup and view all the answers

What is the role of the absolute refractory period in neural signals?

It prevents action potentials from occurring too closely together. Signup and view all the answers

What characterizes the relative refractory period in neurons?

Neurons require a stronger stimulus due to hyperpolarization. Signup and view all the answers

Which neurotransmitter is primarily inhibitory?

GABA Signup and view all the answers

What is the function of neuroactive peptides in the nervous system?

They can modify the response of postsynaptic cells to neurotransmitters. Signup and view all the answers

What does saltatory conduction refer to in the context of neural signaling?

The transmission of signals that occurs in myelinated axons. Signup and view all the answers

Which of the following neurotransmitters is derived from tyrosine?

Norepinephrine Signup and view all the answers

What is the initial step in the process of chemical signaling in neurons?

An action potential travels to the axon terminal. Signup and view all the answers

Which of the following amino acids functions as an excitatory neurotransmitter?

Glutamic Acid Signup and view all the answers

Which statement correctly describes oxidative phosphorylation?

It occurs in the mitochondria and is the biggest ATP payoff. Signup and view all the answers

Which type of transport utilizes carrier proteins to move molecules across a membrane?

Facilitated diffusion. Signup and view all the answers

What characterizes primary active transport in cellular processes?

It relies on established electrochemical gradients. Signup and view all the answers

Coagulative necrosis is defined by which of the following characteristics?

It results in large, bloated cells due to coagulation of proteins. Signup and view all the answers

Which cellular change is described as the shrinkage of the nucleus?

Pyknosis. Signup and view all the answers

What is a consequence of persistent cellular stress?

Atrophy and metaplasia are likely adaptations. Signup and view all the answers

Which of the following statements about liquefactive necrosis is true?

It appears as a collection of liquefied cells forming a cyst-like structure. Signup and view all the answers

Which of the following statements correctly describes passive transport?

It does not require cellular energy for the movement of molecules. Signup and view all the answers

What is the primary function of oxygen in cellular respiration?

To serve as a final electron acceptor in oxidative phosphorylation. Signup and view all the answers

Which statement accurately describes the mechanism of osmosis?

It is the movement of water towards higher solute concentration. Signup and view all the answers

What is the primary reason that oxidative phosphorylation requires oxygen?

It acts as a final electron acceptor. Signup and view all the answers

Which type of transport mechanism is exemplified by glucose movement facilitated by proteins?

Facilitated diffusion Signup and view all the answers

What kind of cellular injury leads to adaptations such as atrophy or metaplasia?

Reversible cell injury Signup and view all the answers

What is the role of chloride channels in creating an inhibitory postsynaptic potential (IPSP)?

They facilitate the movement of chloride ions into the cell, creating a more negative net charge. Signup and view all the answers

Which of the following best describes the process of osmosis?

Water movement across a membrane towards high solute concentration. Signup and view all the answers

Coagulative necrosis is characterized by which of the following properties?

Coagulation of proteins and cell components. Signup and view all the answers

During which specific condition are the sodium channels described as 'inactivated'?

At the peak of the action potential when the membrane reaches 40mV. Signup and view all the answers

What distinguishes secondary active transport from primary active transport?

It does not require ATP directly. Signup and view all the answers

What is the function of the Na/K pump during the hyperpolarization phase?

It restores the membrane potential to its resting state after it drops to -75mV. Signup and view all the answers

Which type of necrosis involves the transformation of tissue into a liquid state?

Liquefactive necrosis Signup and view all the answers

Which of the following best describes the membrane potential once it reaches threshold potential?

It initiates a rapid increase in membrane potential leading to an action potential. Signup and view all the answers

Which statement accurately reflects the stages of Na channels during an action potential?

The inactivated state of Na channels prevents any further Na movement after reaching 40mV. Signup and view all the answers

During glycolysis, how many ATP molecules are produced?

2 Signup and view all the answers

What is the significance of intracellularity in the context of coagulative necrosis?

It is indicative of an irreversible cell injury. Signup and view all the answers

Which of the following is a characteristic feature of primary active transport?

Directly utilizing ATP to move molecules. Signup and view all the answers

What is the primary function of the autonomic nervous system?

Controls the smooth/cardiac muscles and glands Signup and view all the answers

Which part of the neuron initiates an action potential?

Axon hillock Signup and view all the answers

Which statement best describes the role of myelination in neurons?

Facilitates the flow of action potentials along the axon Signup and view all the answers

What is the primary function of Schwann cells in the peripheral nervous system (PNS)?

Myelinate axons to speed up signal transmission Signup and view all the answers

In the context of the nervous system, what does an action potential represent?

A rapid change in the permeability of the neuron's membrane Signup and view all the answers

What type of neuron carries sensory information into the central nervous system (CNS)?

Afferent neuron Signup and view all the answers

Which component of the neuron is responsible for receiving signals from other neurons?

Dendrites Signup and view all the answers

Which of the following statements accurately describes interneurons?

Connect afferent and efferent neurons Signup and view all the answers

What physiological change occurs when the respiratory rate (RR) is increased?

Decreased PCO2 leading to increased pH Signup and view all the answers

Which condition is characterized by low pH and high PCO2

Respiratory Acidosis Signup and view all the answers

What compensatory mechanism occurs in the kidneys in response to metabolic acidosis?

Increased H+ secretion Signup and view all the answers

What is the primary role of bicarbonate in acid-base balance?

It acts as a buffer by neutralizing excess acids Signup and view all the answers

What characterizes metabolic alkalosis?

High pH with high HCO3- Signup and view all the answers

Which of the following scenarios could lead to respiratory alkalosis?

Increased physical exertion Signup and view all the answers

Which type of acid-base disturbance is primarily associated with ketoacidosis?

Metabolic acidosis Signup and view all the answers

What happens to bicarbonate levels in the kidneys during metabolic acidosis?

Decreased reabsorption of bicarbonate Signup and view all the answers

What is the role of phosphates in acid-base balance?

They primarily serve as a buffer system. Signup and view all the answers

In which condition does the body typically manifest increased respiratory rates to compensate?

Metabolic Acidosis Signup and view all the answers

What characteristic of caseous necrosis is specifically related to its appearance?

It looks like cottage cheese. Signup and view all the answers

Which mechanism primarily leads to apoptosis in cells?

Programmed cell death activation. Signup and view all the answers

What effect does hypoxic injury have on the intracellular ion balance?

Increase in intracellular sodium. Signup and view all the answers

Which condition is characterized by the complete loss of blood flow leading to cellular death?

Anoxia. Signup and view all the answers

What immediate cellular change occurs when a cell undergoes osmotic swelling?

Expansion of mitochondria and endoplasmic reticulum. Signup and view all the answers

What is the primary pathological condition associated with excessive free radicals?

Increased membrane permeability. Signup and view all the answers

Which term describes the process by which non-cancerous but dysfunctional cells result from chronic tissue injury?

Metaplasia. Signup and view all the answers

In case of severe mechanical injury to tissues, which of the following might occur?

Potential for necrosis at the injury site. Signup and view all the answers

How does dysplasia differ from hyperplasia in cellular functions?

Dysplasia involves disorganized cellular growth. Signup and view all the answers

Which cellular adaptation occurs in response to decreased functional demand or hormonal support?

Atrophy. Signup and view all the answers

What physiological mechanism is primarily responsible for the increased permeability of membranes during oxidative stress?

Lipid peroxidation of membrane lipids. Signup and view all the answers

Which of the following statements is true about fatty necrosis?

It can result from the release of pancreatic enzymes. Signup and view all the answers

What is the primary cause of intracellular calcium increase during ischemia?

Failure of calcium ATP pumps. Signup and view all the answers

Which term is used for the process of programmed cell death that is crucial for preventing cancer development?

Apoptosis. Signup and view all the answers

Study Notes

Glycolysis and Cellular Respiration

Glycolysis occurs in the cytosol and yields 2 ATP.
The Citric Acid (Krebs) cycle takes place in the mitochondria and also yields 2 ATP.
Oxidative Phosphorylation, located in the mitochondria, generates approximately 32 ATP and is the major ATP-producing step requiring oxygen as the final electron acceptor.
Different food sources enter cellular respiration at various stages.

Cell Transport Mechanisms

Passive Transport: Movement of molecules without energy expenditure.
- Simple Diffusion: Molecules move across membranes down their concentration gradient (e.g., O2, CO2).
- Osmosis: Water moves toward areas of high solute concentration (e.g., water follows Na).
- Facilitated Diffusion: Molecules cross membranes with the assistance of carrier proteins or channels (e.g., glucose).
Active Transport: Molecule movement that requires energy.
- Primary Active Transport: Direct use of ATP to move substances (e.g., Na-K Pump).
- Secondary Active Transport: Utilizes energy from primary transport to drive other substances against their gradients (e.g., Na-glucose cotransporter).

Cellular Stress and Injury Responses

Increased functional demand from stress may lead to adaptations like hypertrophy or hyperplasia.
Reversible injury can include atrophy, metaplasia, and dysplasia with the potential for normal function restoration if stress is relieved within a critical period.
Irreversible cell injury, due to severe stress, results in coagulative necrosis, where cells swell and cytoskeletal structure collapses, leading to tissue death.

Types of Necrosis

Coagulative Necrosis: External cause leads to general tissue death with clumped cell components and loss of structure. Common nuclear changes include:
- Pyknosis: Shrinkage of the nucleus.
- Karyorrhexis: Fragmentation of the nucleus.
- Karyolysis: Disappearance of the nucleus.
Liquefactive Necrosis: Involves a collection of dead cells resulting in a fluid-filled cyst, often in areas with low connective tissue.

Nervous and Endocrine Systems as Control Mechanisms

Nervous System:
- Wired and specific anatomical arrangements between neurons and targets.
- Utilizes neurotransmitters for short-distance signal transmission and coordinates rapid responses.
Endocrine System:
- Wireless setup through glands releasing hormones into the bloodstream for long-distance effects.
- Designed for prolonged activity regulation.

Nervous System Divisions

Central Nervous System: Comprises the brain and spinal cord.
Peripheral Nervous System: Consists of nerves throughout the body, categorized into:
- Afferent Division: Receives and processes sensory information.
- Efferent Division: Sends commands from CNS to muscles and glands.

Resting Membrane Potential

Dominant ions at rest are K+ and negatively charged anions (ICF) vs. Na+, Cl-, and Ca2+ (ECF).
The Na/K Pump exports 3 Na+ for every 2 K+ imported, maintaining ion distribution.
K+ leak channels allow gradual K+ efflux, influenced by concentration gradients.
Equilibrium potential equations describe the electrical balance across membranes for various ions (Nernst Equation).

Action Potentials (AP)

Generated by the influx of Na+ through ligand-gated ion channels due to neurotransmitter binding.
Requires reaching a threshold of -55mV to activate.
Stages of AP include:
- Na+ channels opening and membrane depolarizing.
- AP propagation along the axon aided by saltatory conduction in myelinated fibers.

Chemical Communication in Neurons

Communication can be electrical or chemical through synapses.
Neurotransmitters include:
- Amino Acids: Glutamate (excitatory), GABA (inhibitory), Glycine (inhibitory).
- Monoamines: Includes neurotransmitters like acetylcholine and serotonin.
- Catecholamines: Derived from tyrosine, including dopamine, norepinephrine, and epinephrine.

Neuroactive Peptides

Peptides that modify responses without acting as classic neurotransmitters.
Examples include somatostatin, neurotensin, and substance P. They can modify neurotransmitter effects and enhance sensitivity in postsynaptic cells.

Acid-Base Regulation

Lungs regulate blood pH by adjusting respiratory rate (RR) and depth.
Increased RR lowers carbon dioxide (CO2) levels, decreasing partial pressure of CO2 (PCO2) and raising pH.
Decreased RR retains CO2, increasing PCO2 and lowering pH.
Kidney regulation involves reabsorbing bicarbonate (HCO3-) and secreting hydrogen ions (H+).
Higher HCO3- reabsorption raises pH, while lower reabsorption decreases pH.
Kidney response is slower, taking hours to days.
Approximately 60% of blood CO2 is transported as bicarbonate (HCO3-).

Buffer Systems

Hemoglobin acts as both an acid (HHb) and a base (Hb-).
Proteins also function as buffers, existing in both acid (HPr) and base forms (Pr-).
Phosphates include dihydrogen phosphate (H2PO4-) and hydrogen phosphate (HPO4=), used in energy storage (ATP).
Buffer systems operate within specific pH ranges, allowing physiological pH maintenance.

Respiratory Disorders

Respiratory Acidosis:
- Indicators: low pH, high PCO2, normal HCO3-.
- Causes: hyperventilation or inadequate gas exchange, leading to CO2 accumulation.
Respiratory Alkalosis:
- Indicators: high pH, low PCO2, normal HCO3-.
- Causes: excessive hyperventilation, resulting in CO2 depletion.

Metabolic Disorders

Metabolic Acidosis:
- Indicators: low pH, normal PCO2, low HCO3-.
- Causes: excessive production of non-carbonic acids (ketoacidosis, uremia) or bicarbonate loss (diarrhea, renal failure).
Metabolic Alkalosis:
- Indicators: high pH, normal PCO2, high HCO3-.
- Causes: loss of non-carbonic acids (vomiting, GI suctioning) or excessive bicarbonate intake.

Cell Metabolism

Energy metabolism involves breaking down nutrients to generate ATP.
Three steps:
- Glycolysis: occurs in the cytosol, yielding 2 ATP.
- Krebs Cycle: occurs in mitochondria, yielding 2 ATP.
- Oxidative Phosphorylation: occurs in mitochondria, yielding approximately 32 ATP; utilizes oxygen as the final electron acceptor.

Cell Transport Mechanisms

Passive Transport:
- Simple Diffusion: movement of gasses like O2 and CO2 across membranes without energy.
- Osmosis: water moves towards higher solute concentration without energy.
- Facilitated Diffusion: molecules like glucose require carrier proteins.
Active Transport:
- Secondary Active Transport: uses ATP for moving substances against their gradient (e.g., Na-K Pump).
- Primary Active Transport: uses the established electrochemical gradient to transport substances (e.g., Na-glucose cotransporter).

Cellular Stress and Injury

Cellular responses to stress may lead to adaptations or injury.
Adaptation refers to changes like hypertrophy and hyperplasia in response to increased demand.
Reversible Cell Injury can manifest as atrophy, metaplasia, or dysplasia. Immediate reversal can restore normal function.
Coagulative Necrosis: cell death from external factors, characterized by cell swelling and coagulation of protein.
Liquefactive Necrosis: tissue liquefies due to lack of connective tissue, producing a cyst-like appearance in regions with minimal connective tissue.### Caseous and Fat Necrosis
Caseous necrosis resembles cottage cheese, characterized by a loose connective tissue structure holding dead cells together.
Commonly found in lymph nodes affected by tuberculosis (TB) in the lungs.
Fat necrosis is cell death in fatty tissues, typically in the pancreas and breast, resulting from the release of cellular contents that react with fat, leading to saponification.

Apoptosis

Apoptosis is programmed cell death integral to organisms, preventing the emergence of cancerous cells.
Activation can occur intrinsically or extrinsically, followed by cell shrinkage, chromatin condensation, nuclear collapse, apoptotic body formation, and lysis of these bodies.
Triggers include viral infections, DNA damage, membrane or mitochondrial damage, and immune cell induction.

Mechanisms of Cell Injury

Hypoxic injury results from insufficient oxygen supply, often due to ischemia, which reduces blood flow and oxygen delivery.
Anoxia denotes a complete loss of blood flow and oxygen delivery, typically due to a blockage.
Reperfusion injury occurs from inflammatory reactions following the restoration of blood flow, damaging tissues.
Free radical injury is caused by reactive oxygen species (e.g., superoxide, hydroxyl radical) that can result from metabolism, inflammation, pollution, and smoking.

Cell Injury Outcomes

Damage leads to lipid peroxidation, affecting membrane integrity, altering enzymatic activity, and causing DNA damage, which may elevate cancer risks.
Mechanical injuries, extreme temperatures, and chemical exposure also contribute to cellular damage.

Cellular Adaptations

Hypertrophy: Increase in cell size due to heightened functional demands; often occurs in tandem with hyperplasia (cell number increase).
Hyperplasia: Increase in cell number while cell size remains constant, often seen in response to hormonal stimulation or chronic injury.
Atrophy: Reduction in cell size while maintaining the same number of cells in response to decreased functional demands.
Metaplasia: Reversion of one type of adult cell to another in response to injury; often seen in epithelial tissues (e.g., smoker's lung).
Dysplasia: Unregulated cell division leading to abnormal cell growth; considered precancerous and can propagate to malignancies.

Changes in Cell Storage

Normal cellular storage includes fats and glycogen; abnormalities in digestion may lead to accumulation (e.g., tattoos).
Water accumulation results from hypoxic injury, leading to cell swelling.
Lipid accumulation is exemplified in Tay Sachs disease and fatty liver disease due to enzyme deficiencies or chronic alcohol exposure.

Nervous System Control

Homeostatic control involves sensors, integrators, effectors, and compensatory reactions to return variables to set points via negative feedback.
The autonomic nervous system manages involuntary functions, subdivided into sympathetic (fight/flight) and parasympathetic (rest/digest) systems.

Nervous Tissue and Neurons

Ramón y Cajal advanced neuroscience by detailing neuron structures through specialized staining.
Neurons consist of a cell body, dendrites (receive input), axons (transmit signals), and myelin (speeding up signal transmission).
Types of neurons include afferent (sensory), interneurons (connecting others), and efferent (motor).
Action potentials rely on the opening and closing of sodium and potassium channels, with a threshold of -55mV for initiation.

Action Potential Dynamics

States of sodium channels (closed, open, inactivated) are critical in the action potential process.
Hyperpolarization occurs after an action potential as potassium channels remain open, causing a drop to -75mV, emphasizing the importance of the Na/K pump in repolarization and resting potential management.

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Description

This quiz covers the main stages of cellular respiration, including glycolysis, the citric acid cycle, and oxidative phosphorylation. Learn about the locations of these processes within the cell and their ATP yields. Test your knowledge of this essential cellular energy conversion pathway!