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Negative feedback mechanisms in the body require continuous adjustments.
Negative feedback mechanisms in the body require continuous adjustments.
True
Positive feedback systems tend to stabilize physiological processes over time.
Positive feedback systems tend to stabilize physiological processes over time.
False
An example of negative feedback is the secretion of insulin when blood glucose levels rise.
An example of negative feedback is the secretion of insulin when blood glucose levels rise.
True
Feed-forward control is a response made in anticipation of a change.
Feed-forward control is a response made in anticipation of a change.
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The process of blood clotting is an example of feed-forward control.
The process of blood clotting is an example of feed-forward control.
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A multicellular organism consists of specialized cells that interact for survival.
A multicellular organism consists of specialized cells that interact for survival.
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Shivering before entering cold water is an example of negative feedback control.
Shivering before entering cold water is an example of negative feedback control.
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Human beings have between 10 to 50 trillion cells in their bodies.
Human beings have between 10 to 50 trillion cells in their bodies.
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Differentiation leads to cells varying in size and shape based on their unique functions.
Differentiation leads to cells varying in size and shape based on their unique functions.
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LH increase before ovulation is an example of negative feedback.
LH increase before ovulation is an example of negative feedback.
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Co-transporters move one moiety in the same direction as Na+ while counter-transporters move moieties in opposite directions.
Co-transporters move one moiety in the same direction as Na+ while counter-transporters move moieties in opposite directions.
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Simple diffusion requires special membrane proteins.
Simple diffusion requires special membrane proteins.
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Active transport does not require energy for movement across the membrane.
Active transport does not require energy for movement across the membrane.
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The resting membrane potential of a cell is approximately +70 mV.
The resting membrane potential of a cell is approximately +70 mV.
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Changes in the resting potential can influence the basic signaling properties of neurons.
Changes in the resting potential can influence the basic signaling properties of neurons.
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Extracellular fluid (ECF) makes up two-thirds of total body water.
Extracellular fluid (ECF) makes up two-thirds of total body water.
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Plasma constitutes one-fourth of the extracellular fluid.
Plasma constitutes one-fourth of the extracellular fluid.
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Interstitial fluid (ISF) surrounds the cells and provides a fluid environment.
Interstitial fluid (ISF) surrounds the cells and provides a fluid environment.
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Intracellular fluid (ICF) typically has a high concentration of sodium ions (Na+).
Intracellular fluid (ICF) typically has a high concentration of sodium ions (Na+).
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Total body water in a male weighing 70 kg is approximately 42 liters.
Total body water in a male weighing 70 kg is approximately 42 liters.
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The term homeostasis refers to the maintenance of a relatively constant internal environment.
The term homeostasis refers to the maintenance of a relatively constant internal environment.
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The total volume of interstitial fluid (ISF) in a 70 kg male is 10.5 liters.
The total volume of interstitial fluid (ISF) in a 70 kg male is 10.5 liters.
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Intracellular fluid (ICF) is conditioned solely by the plasma.
Intracellular fluid (ICF) is conditioned solely by the plasma.
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The cell membrane is permeable to water-soluble substances.
The cell membrane is permeable to water-soluble substances.
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Phospholipids have both hydrophilic and hydrophobic properties.
Phospholipids have both hydrophilic and hydrophobic properties.
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Active processes require energy in the form of ATP.
Active processes require energy in the form of ATP.
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Simple diffusion only allows large, charged molecules to pass through the cell membrane.
Simple diffusion only allows large, charged molecules to pass through the cell membrane.
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Facilitated diffusion requires a carrier protein to help transport substances across the membrane.
Facilitated diffusion requires a carrier protein to help transport substances across the membrane.
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Osmosis is solely the movement of lipid-soluble molecules.
Osmosis is solely the movement of lipid-soluble molecules.
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The net movement of molecules is zero at equilibrium.
The net movement of molecules is zero at equilibrium.
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The majority of the plasma membrane is composed of carbohydrates.
The majority of the plasma membrane is composed of carbohydrates.
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Lipid-soluble substances can readily cross the cell membrane.
Lipid-soluble substances can readily cross the cell membrane.
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Secondary active transport does not require direct energy input.
Secondary active transport does not require direct energy input.
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Active transport requires energy to move substances from regions of lower concentration to regions of higher concentration.
Active transport requires energy to move substances from regions of lower concentration to regions of higher concentration.
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Primary active transport uses energy derived indirectly from ionic concentration differences.
Primary active transport uses energy derived indirectly from ionic concentration differences.
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The Na+/K+ pump moves three sodium ions into the cell and two potassium ions out of the cell.
The Na+/K+ pump moves three sodium ions into the cell and two potassium ions out of the cell.
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Secondary active transport depends on the movement of one substance 'downhill' to drive the 'uphill' transport of another substance.
Secondary active transport depends on the movement of one substance 'downhill' to drive the 'uphill' transport of another substance.
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The hydrolysis of ATP is directly required for primary active transport to function.
The hydrolysis of ATP is directly required for primary active transport to function.
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Calcium ions are actively transported to maintain high intracellular Ca++ levels.
Calcium ions are actively transported to maintain high intracellular Ca++ levels.
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The H+/K+ pump is also known as the proton pump and is found in the stomach.
The H+/K+ pump is also known as the proton pump and is found in the stomach.
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Facilitated diffusion and active transport both require carrier molecules but only active transport needs energy.
Facilitated diffusion and active transport both require carrier molecules but only active transport needs energy.
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Coupled transport in secondary active transport can occur without the simultaneous presence of Na+ and glucose.
Coupled transport in secondary active transport can occur without the simultaneous presence of Na+ and glucose.
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The skeletal muscles are responsible for pumping the blood.
The skeletal muscles are responsible for pumping the blood.
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Tissues are groups of similar cells that work together on one task.
Tissues are groups of similar cells that work together on one task.
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Cells serve as the smallest structural unit capable of performing life processes.
Cells serve as the smallest structural unit capable of performing life processes.
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There are 8 levels of organization in the human body.
There are 8 levels of organization in the human body.
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Extracellular fluid consists of both plasma and interstitial fluid.
Extracellular fluid consists of both plasma and interstitial fluid.
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Smooth muscles can be found in the walls of blood vessels and organs.
Smooth muscles can be found in the walls of blood vessels and organs.
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The chemical level of organization consists solely of cells.
The chemical level of organization consists solely of cells.
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The heart and lungs are protected by the chest cavity formed by the skull.
The heart and lungs are protected by the chest cavity formed by the skull.
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Osmosis is the movement of water from regions of lower concentration of water to regions of higher concentration of water.
Osmosis is the movement of water from regions of lower concentration of water to regions of higher concentration of water.
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Isotonic solutions have equal osmotic pressure to the cells they interact with.
Isotonic solutions have equal osmotic pressure to the cells they interact with.
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In hypertonic solutions, cells will gain water and swell.
In hypertonic solutions, cells will gain water and swell.
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The osmotic pressure inside human cells is equivalent to a 0.9% solution of sodium chloride.
The osmotic pressure inside human cells is equivalent to a 0.9% solution of sodium chloride.
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Infusing isotonic saline is less effective than infusing an isoosmotic solution of a penetrating solute like urea for restoring blood volume.
Infusing isotonic saline is less effective than infusing an isoosmotic solution of a penetrating solute like urea for restoring blood volume.
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The total body water of a healthy adult is approximately 50% of their body weight.
The total body water of a healthy adult is approximately 50% of their body weight.
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A health female adult body is composed of more fluid than a health male adult body.
A health female adult body is composed of more fluid than a health male adult body.
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As age increases, the total body water content tends to increase.
As age increases, the total body water content tends to increase.
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Capillary action is one of the properties of water that enables it to serve as an excellent solvent.
Capillary action is one of the properties of water that enables it to serve as an excellent solvent.
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About 80% of the body of a newborn is composed of fluid.
About 80% of the body of a newborn is composed of fluid.
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The respiratory system is responsible for taking in nutrients and eliminating waste from the body.
The respiratory system is responsible for taking in nutrients and eliminating waste from the body.
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The connective tissue binds all the primary tissues in an organ together.
The connective tissue binds all the primary tissues in an organ together.
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Water is the most difficult liquid to freeze or boil due to its specific heat properties.
Water is the most difficult liquid to freeze or boil due to its specific heat properties.
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Smooth muscle tissue is present in the stomach and plays a role in muscle contraction.
Smooth muscle tissue is present in the stomach and plays a role in muscle contraction.
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Intracellular fluid (ICF) typically has a high concentration of potassium ions (K+).
Intracellular fluid (ICF) typically has a high concentration of potassium ions (K+).
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Positive feedback mechanisms generally require continuous adjustments.
Positive feedback mechanisms generally require continuous adjustments.
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Feed-forward control only occurs after a change has been detected.
Feed-forward control only occurs after a change has been detected.
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Blood glucose levels decrease when insulin is secreted.
Blood glucose levels decrease when insulin is secreted.
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Differentiation in cells leads to identical cell sizes and shapes.
Differentiation in cells leads to identical cell sizes and shapes.
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Shivering is an example of positive feedback.
Shivering is an example of positive feedback.
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The human body contains approximately 50-100 trillion cells.
The human body contains approximately 50-100 trillion cells.
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Urination is an example of negative feedback in the body.
Urination is an example of negative feedback in the body.
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Na+ inflow is crucial in generating nerve signals.
Na+ inflow is crucial in generating nerve signals.
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Specialized cells contribute to the overall survival of multicellular organisms.
Specialized cells contribute to the overall survival of multicellular organisms.
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Positive feedback mechanisms stabilize physiological processes.
Positive feedback mechanisms stabilize physiological processes.
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Cell membranes are impermeable to small polar covalent molecules like CO2.
Cell membranes are impermeable to small polar covalent molecules like CO2.
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Facilitated diffusion requires energy input to transport substances across the membrane.
Facilitated diffusion requires energy input to transport substances across the membrane.
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Charged inorganic ions such as Na+ can pass freely through the cell membrane via simple diffusion.
Charged inorganic ions such as Na+ can pass freely through the cell membrane via simple diffusion.
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Simple diffusion can occur when there is a concentration difference across the membrane.
Simple diffusion can occur when there is a concentration difference across the membrane.
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Lipid soluble substances can easily diffuse through the cell membrane.
Lipid soluble substances can easily diffuse through the cell membrane.
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Water-soluble substances are typically transported through simple diffusion.
Water-soluble substances are typically transported through simple diffusion.
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Glucose is a large polar molecule that can diffuse directly through the cell membrane.
Glucose is a large polar molecule that can diffuse directly through the cell membrane.
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During simple diffusion, substances must always move against their concentration gradient.
During simple diffusion, substances must always move against their concentration gradient.
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Membrane proteins aid in the facilitated diffusion of molecules like K+ and glucose.
Membrane proteins aid in the facilitated diffusion of molecules like K+ and glucose.
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The degree of diffusion for substances is primarily determined by their solubility in lipids.
The degree of diffusion for substances is primarily determined by their solubility in lipids.
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Study Notes
Body Fluids
- Extracellular Fluid (ECF) makes up 1/3 of total body water, and is the fluid environment cells live in.
- It comprises Plasma, found inside blood cells, and Interstitial Fluid, which surrounds cells.
- Intracellular Fluid (ICF) makes up 2/3 of total body water and is found within all body cells. It has high levels of potassium (K+) and lower levels of sodium (Na+).
- ICF has a negative charge due to the presence of proteins.
- The total body water content for a 70kg male is roughly 42 liters.
- This results in 28 liters of ICF and 14 liters of ECF.
- Plasma accounts for 3.5 liters of ECF and Interstitial Fluid accounts for 10.5 liters.
Balancing Internal and External Environments
- Cells exchange nutrients and wastes with their surroundings.
- The intracellular fluid is conditioned by the interstitial fluid.
- The interstitial fluid is conditioned by the plasma.
- The plasma is conditioned by the organ systems it passes through.
- The internal environment refers to the fluid surrounding cells (Extracellular Fluid).
Homeostasis
- Homeostasis refers to the maintenance of a relatively constant and stable internal environment (extracellular fluids).
- It is often regulated by negative feedback control.
Negative Feedback
- An initial change leads to a response that suppresses the initial change.
- For example, eating food increases glucose levels in the blood, the pancreas releases insulin to lower blood glucose levels.
- Negative feedback is used for frequent adjustments of conditions like body temperature blood pressure and glucose regulation.
Positive Feedback
- An initial change leads to a response that increases the initial change.
- It is short-lived and not required for continuous adjustments.
- Examples include: blood clotting, urination, LH increase before ovulation, Na+ inflow in the generation of nerve signals, and uterine contractions during childbirth.
Feed-Forward Control
- A response is made in anticipation of a change.
- The stimulus directly affects the control system before the action of feedback.
- This prepares the body for the change.
- Examples include shivering before diving into cold water and salivation in response to smelling food.
Human Cell
- The human body is multicellular, composed of different types of cells.
- An estimated 50-100 trillion cells are present in the human body.
- Differentiation is the process of cells becoming specialized.
- The unique functions of cells result in varied sizes and shapes.
- The cell membrane is selectively permeable.
- It allows lipid-soluble materials to cross, while lipid-insoluble (water-soluble) materials need channels.
- Cell membranes contain 40% protein, 55% lipid, and 3 % carbohydrates.
Cell Membrane
- Phospholipids are the major component of the cell membrane.
- They have a bilayer structure.
- The water-soluble heads form the surface, while the water-insoluble tails form the interior.
- It is permeable to lipid-soluble substances.
Movements Into and Out of the Cell
- Passive processes move substances down a concentration gradient, do not need ATP and include simple diffusion, facilitated diffusion, and osmosis.
- Active processes move substances against a concentration gradient, need energy, and include primary active transport and secondary active transport.
Simple Diffusion
- It is the movement of a substance from a region of higher concentration to a region of lower concentration.
- It doesn't require a carrier molecule or energy.
- It is affected by factors like the concentration gradient, temperature, membrane permeability, and surface area.
Facilitated Diffusion
- It is the movement of a substance from a region of higher concentration to a region of lower concentration.
- It requires a carrier or transporter molecule but does not require energy.
- Carrier or transporter molecules increase the rate of diffusion.
- It is specific and affected by saturation.
Osmosis
- It is the movement of water molecules from a region of higher water concentration to a region of lower water concentration across a selectively permeable membrane.
- It is driven by differences in water potential or osmotic pressure.
- It is crucial for maintaining cell volume and fluid balance.
- It is affected by the concentration of solutes on each side of the membrane.
- It relies on aquaporins (specific water channels) for efficient transport.
Active Transport
- It is the movement of a substance from a region of lower concentration to a region of higher concentration.
- It requires energy and a carrier protein.
- It maintains concentration gradients and is crucial for cellular functions.
Primary Active Transport
- It directly uses energy from ATP hydrolysis to move the substance against its concentration gradient.
- It involves carrier proteins that bind to the substance and undergo conformational changes to move it across the membrane.
- Examples include the Na+/K+ pump, Ca++ active transport, active transport of H+ in the stomach and kidneys, and the H+/K+ pump.
Secondary Active Transport
- It uses the potential energy stored in an electrochemical gradient established by primary active transport.
- It couples the movement of one substance (e.g., Na+) down its electrochemical gradient with the movement of another substance (e.g., glucose) against its concentration gradient.
- Examples include glucose and amino acid co-transport and Na+/Ca++ counter-transport.
Membrane Resting Potential
- It is a constant potential difference across the resting cell membrane.
- The cell's ability to fire an action potential is dependent on maintaining a resting potential of approximately -70mV.
- Changes in resting potential influence basic neuronal signaling properties.
Membrane Potential
- The membrane potential is the difference in electrical potential across a cell membrane.
- It is influenced by:
- The concentration gradients of ions (Na+, K+, Cl-, Ca++) across the membrane.
- The permeability of the membrane to these ions.
- The activity of ion pumps (e.g., the Na+/K+ pump).
- Resting potential is a specialized case when the membrane is not transmitting signals.
- The membrane potential is dynamic and changes in response to stimuli, like nerve impulses.
- It plays a crucial role in various cellular processes, including:
- Nerve signal transmission.
- Muscle contraction.
- Hormone release.
- Sensory perception.
- Cellular communication.
- Maintaining cell volume and shape.
Introduction
- The body is a complex structure with each organ serving a vital role
- The structure of each organ helps it perform its function
- For example, the chest cavity protects the heart and lungs, and changes shape to enable breathing
Levels of Organization
- The body is organized into levels of increasing complexity, from the chemical level to the organismic level
- Chemical level: involves atoms and molecules like Oxygen, Nitrogen, Carbon, Hydrogen, and molecules such as water, CO2, CHO, and proteins.
- Cellular level: comprises cells, the basic unit of life, responsible for performing the necessary functions of life.
- Tissue level: composed of similar cells with the same structure and specialized function working together, Examples include epithelial, connective, muscle, and nerve tissues.
- Organ level: made up of two or more tissues working together towards a common function, Examples of organs are the skin, femur, heart, kidney.
- System level: a group of related organs with a common function. For example, the digestive system.
- Organismic level: the whole human being, a complex organism made up of all the above levels.
Body Fluids
- The total body water of a healthy adult is 60% of their body weight
- Body water content decreases with age and is lower in females due to higher fat content.
- Water is the most suitable liquid for the body due to its specific heat, capillary action, solvent properties, and role in redox reactions.
Feedback Systems
- Feedback systems maintain homeostasis in the body.
- Negative feedback: a mechanism that reduces or reverses a change in the body to maintain equilibrium, for example blood glucose regulation.
- Positive feedback: a mechanism that amplifies an initial change, for example, blood clotting, LH increase before ovulation, and contraction of the uterus during childbirth.
- Feed-forward control: a mechanism that anticipates a change and prepares the body for it, for example, shivering before diving into cold water, or salivation when we smell food before eating.
The Human Cell
- The human body is multicellular and contains 50-100 trillion cells.
- Cells differentiate to specialize in various functions, contributing to the survival of the organism.
Cell Membrane Physiology
- Simple Diffusion: movement of non-polar, lipid-soluble molecules, small polar covalent bonds, and water across the cell membrane.
- Facilitated Diffusion: movement of lipid-insoluble, water-soluble substances across the membrane with the help of membrane proteins.
- Osmosis: movement of water through a selectively permeable membrane from regions of higher concentration to regions of lower concentration, it is important for functions at the cellular and tissue levels.
Osmotic Pressure and Solutions
- Osmotic pressure of a solution depends on the concentration of solutes.
- Hypotonic solution: the osmotic pressure of the solution is lower than the osmotic pressure of the cells (water enters the cells).
- Hypertonic solution: the osmotic pressure of the solution is higher than the osmotic pressure of the cells (water exits the cells).
- Isotonic solution: the osmotic pressure of the solution is equal to the osmotic pressure of the cells (water movement is balanced).
Example: Blood Volume Restoration
- Infusing isotonic NaCl solution is better than an isoosmotic solution of a penetrating solute (such as urea) because only isotonic NaCl solution can maintain blood volume at the proper level; urea would diffuse into the cells, leading to fluid accumulation and cellular swelling.
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Description
Test your knowledge on the composition and functions of body fluids. This quiz covers concepts such as Intracellular Fluid (ICF), Extracellular Fluid (ECF), and how cells interact with their environment. Understand the importance of fluid balance in human physiology.
