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Which type of molecules can easily diffuse through the cell membrane?
Which type of molecules can easily diffuse through the cell membrane?
What primarily determines the degree of diffusion of substances through the cell membrane?
What primarily determines the degree of diffusion of substances through the cell membrane?
Which substance would require facilitated diffusion to cross the membrane?
Which substance would require facilitated diffusion to cross the membrane?
In simple diffusion, the movement of substances occurs down their:
In simple diffusion, the movement of substances occurs down their:
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Which of the following is NOT permeable through the cell membrane by simple diffusion?
Which of the following is NOT permeable through the cell membrane by simple diffusion?
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What is the primary component of extracellular fluid (ECF)?
What is the primary component of extracellular fluid (ECF)?
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Which of the following is true about intracellular fluid (ICF)?
Which of the following is true about intracellular fluid (ICF)?
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What percentage of total body weight is accounted for by intracellular fluid?
What percentage of total body weight is accounted for by intracellular fluid?
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If a male weighs 70 kg, how much of that weight is total body water?
If a male weighs 70 kg, how much of that weight is total body water?
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What is the relationship between intracellular fluid and interstitial fluid?
What is the relationship between intracellular fluid and interstitial fluid?
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What does homeostasis primarily involve?
What does homeostasis primarily involve?
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Which fluid primarily bathes the cells and constitutes the internal environment?
Which fluid primarily bathes the cells and constitutes the internal environment?
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Which compartment has the highest water content in the body?
Which compartment has the highest water content in the body?
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What is the major component of the plasma membrane?
What is the major component of the plasma membrane?
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What type of molecules are the heads of phospholipids described as?
What type of molecules are the heads of phospholipids described as?
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Which process requires energy for the movement of substances across the cell membrane?
Which process requires energy for the movement of substances across the cell membrane?
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What type of substances can diffuse through the lipid bilayer easily?
What type of substances can diffuse through the lipid bilayer easily?
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Which of the following is NOT a type of passive transport?
Which of the following is NOT a type of passive transport?
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What occurs during osmosis?
What occurs during osmosis?
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What is the characteristic of the tails of phospholipids?
What is the characteristic of the tails of phospholipids?
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Which passive process involves movement through a specific channel?
Which passive process involves movement through a specific channel?
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In which direction does passive transport generally occur?
In which direction does passive transport generally occur?
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Which term describes the net movement of particles until equilibrium is reached?
Which term describes the net movement of particles until equilibrium is reached?
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What is the main function of connective tissue in an organ?
What is the main function of connective tissue in an organ?
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What percentage of total body weight is made up of water in a healthy adult?
What percentage of total body weight is made up of water in a healthy adult?
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Which body system is responsible for gas exchange?
Which body system is responsible for gas exchange?
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How does body water percentage change with age?
How does body water percentage change with age?
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Which liquid has the highest specific heat, making it difficult to boil or freeze?
Which liquid has the highest specific heat, making it difficult to boil or freeze?
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What role does the nervous tissue play in the stomach?
What role does the nervous tissue play in the stomach?
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What is the primary function of the urinary system?
What is the primary function of the urinary system?
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In which organ would you find a combination of epithelial, muscular, nervous, and connective tissues?
In which organ would you find a combination of epithelial, muscular, nervous, and connective tissues?
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Why is water considered an excellent solvent?
Why is water considered an excellent solvent?
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Which of the following statements is correct regarding body systems?
Which of the following statements is correct regarding body systems?
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What is the main function of insulin in the body?
What is the main function of insulin in the body?
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Which of the following is an example of positive feedback?
Which of the following is an example of positive feedback?
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In feed-forward control, what does the control system do?
In feed-forward control, what does the control system do?
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What is differentiation in the context of human cells?
What is differentiation in the context of human cells?
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What happens during the contractions of the uterus during childbirth?
What happens during the contractions of the uterus during childbirth?
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Why is negative feedback more common in physiological systems?
Why is negative feedback more common in physiological systems?
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What physiological response occurs when diving into cold water?
What physiological response occurs when diving into cold water?
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How does the body respond to smelling food before eating?
How does the body respond to smelling food before eating?
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Which feedback system is employed for situations needing frequent adjustments?
Which feedback system is employed for situations needing frequent adjustments?
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What is a key characteristic of human cells?
What is a key characteristic of human cells?
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Study Notes
Body Fluids
- Extracellular fluid (ECF) is the fluid environment where cells live (outside the cells). It contains ions, oxygen, nutrients, and waste products.
- ECF contains 2 components: Plasma (inside blood cells) and Interstitial fluid (around the cells).
- Intracellular fluid (ICF) is the fluid inside all body cells. It contains high levels of potassium (K+) and less sodium (Na+).
- ICF has a negative charge due to proteins.
Water in Body Fluids
- Total body water is around 60% of body weight in healthy adults, varying with age and gender.
- Water content decreases with age.
- Women have a lower water content (50-55%) because they have more fatty tissues.
Why Water?
- High specific heat capacity of water makes it resistant to boiling or freezing.
- Capillary action enables movement of water in tears and breastfeeding.
- Water is an excellent solvent for ions like sodium (Na+), potassium (K+), and chloride (Cl−).
- Water participates in redox reactions to kill bacteria.
Internal and External Environment
- Cells exchange nutrients and waste products with their surroundings.
- ICF is influenced by interstitial fluid, which is influenced by plasma, which is in turn influenced by the organs it passes through and the external environment.
- Internal environment refers to the fluids surrounding cells (ECF).
Homeostasis
- Homeostasis refers to maintaining a relatively constant and stable internal environment (extracellular fluids).
Levels of Organization
- Cell: smallest living unit, capable of carrying out life functions.
- Tissue: group of similar cells that perform a specific function, e.g., epithelial tissue, connective tissue, muscular tissue, nervous tissue.
- Organ: consists of two or more types of tissues working together, e.g., stomach, heart, kidney.
- Body System: a collection of related organs with a common function, e.g., digestive system, skeletal system.
- Organism: a complete living individual.
Body Openings
- There are 3 openings between the inside and outside of the human body:
- Respiratory system: takes in oxygen (O2) and eliminates carbon dioxide (CO2).
- Digestive system: takes in food and eliminates unabsorbed food.
- Urinary system: eliminates waste products from the body.
Cell Membrane
- The cell membrane is selectively permeable, allowing some substances to pass through while preventing others.
- It allows lipid-soluble materials to cross but prevents lipid-insoluble (water-soluble) materials.
- Water-soluble substances pass through channels.
- The cell membrane is composed primarily of phospholipids.
- It has a phospholipid bilayer, with water-soluble “heads” forming the surface (hydrophilic) and water-insoluble “tails” forming the interior (hydrophobic).
Movement Across the Cell Membrane
- Substances move across the cell membrane by both active and passive processes:
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Passive processes occur down a concentration gradient (high concentration to an area of low concentration) and do not require energy.
- Simple diffusion: direct movement across the membrane.
- Facilitated diffusion: movement by membrane proteins.
- Osmosis: movement of water across the membrane.
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Active processes occur against a concentration gradient and require energy (ATP).
- Primary active transport: directly uses ATP.
- Secondary active transport: uses the energy of another molecule.
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Passive processes occur down a concentration gradient (high concentration to an area of low concentration) and do not require energy.
Simple Diffusion
- The substances move directly through intermolecular spaces (directly through the cell membrane) of the membrane, commonly lipid-soluble substances and gases.
- It occurs whenever there is a concentration difference across a membrane permeable to the diffusing substance.
- It is energy-independent.
Facilitated Diffusion
- The movement of lipid-insoluble or water-soluble substances across the membrane down their concentration gradients by aid of membrane proteins.
- Substances that use this method include K+, Na+, Ca2+, glucose, amino acids, and urea.
Further Explanation
- Simple diffusion allows small, non-polar molecules like oxygen (O2) and small polar molecules like carbon dioxide (CO2) to pass through the cell membrane.
- Large polar molecules like glucose and charged inorganic ions like sodium (Na+) need facilitated diffusion or active transport to cross the cell membrane.
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Description
Test your knowledge about body fluids and the importance of water in human physiology. Explore concepts such as extracellular and intracellular fluid composition, water distribution, and its unique properties. This quiz will deepen your understanding of the role of water and fluid balance in the body.
