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Questions and Answers
What is the primary function of the cell membrane?
What is the primary function of the cell membrane?
What are the two main types of cell processes?
What are the two main types of cell processes?
What are the two types of transport mechanisms across the cell membrane?
What are the two types of transport mechanisms across the cell membrane?
Passive and Active
The cell membrane is composed mostly of lipids.
The cell membrane is composed mostly of lipids.
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Passive transport moves substances from a high concentration area to a low concentration area.
Passive transport moves substances from a high concentration area to a low concentration area.
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Active transport requires energy to move substances against their concentration gradient.
Active transport requires energy to move substances against their concentration gradient.
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What is the name of the process by which the cell takes in substances from its surroundings?
What is the name of the process by which the cell takes in substances from its surroundings?
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What is the name of the process by which the cell releases substances from its interior?
What is the name of the process by which the cell releases substances from its interior?
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What type of junction allows for direct communication between cells?
What type of junction allows for direct communication between cells?
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Tight junctions prevent the passage of substances between cells.
Tight junctions prevent the passage of substances between cells.
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What type of transport mechanism does osmosis rely on?
What type of transport mechanism does osmosis rely on?
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What is the name of the process by which fluid is forced through a semipermeable membrane due to a pressure gradient?
What is the name of the process by which fluid is forced through a semipermeable membrane due to a pressure gradient?
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What is the structural unit of the nervous system?
What is the structural unit of the nervous system?
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What are the two main components of a neuron?
What are the two main components of a neuron?
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What is the function of myelin sheath in a neuron?
What is the function of myelin sheath in a neuron?
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What is the function of dendrites in a neuron?
What is the function of dendrites in a neuron?
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What is the function of the axon in a neuron?
What is the function of the axon in a neuron?
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What is a stimulus?
What is a stimulus?
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The cell body is the largest part of a neuron.
The cell body is the largest part of a neuron.
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What is the name of the gap between two neurons where communication occurs?
What is the name of the gap between two neurons where communication occurs?
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Study Notes
Human Body Composition
- Human body is composed of 60% water and 40% solids
- Solids are comprised of:
- 18% protein
- 15% fat
- 1% minerals (organic)
Intracellular Fluid (ICF) and Extracellular Fluid (ECF)
- ICF (intracellular fluid) accounts for 40% of total body water.
- ECF (extracellular fluid) accounts for 20%.
- ICF is within cells.
- ECF is outside of cells, including:
- Intravascular fluid (plasma)
- Interstitial fluid
Calculating Total Body Water (TBW)
- TBW = 0.60 x body weight (kg)
- Example for a 70 kg person:
- TBW = 0.60 * 70 = 42L
- ICF (28 Liters)
- ECF (14 Liters)
ECF and ICF Composition
-
ECF:
- Main cations: Na+, K+
- Main anions: HCO3⁻, HPO₄²⁻, protein
-
ICF:
- Main cations: K+, Mg2+
- Main anions: proteins, phosphate (HPO₄²⁻)
pH and Osmolarity
- pH of both ICF and ECF is approximately 7.4.
- Osmolarity of both is also similar.
Fluid Intake and Output
- Input: 2300 ml/day (drinking, food)
- Output: 2300 ml/day (urine, sweat, feces, breathing)
Water Balance Disorders
- Dehydration: Loss of water exceeds intake
- Causes: excessive sweating, vomiting, diarrhea
- Symptoms: dry mouth, sunken eyes, fatigue
Treatment of Dehydration
- Giving the patient 0.9% NaCl (normal saline) or glucose (5%) solution.
Cell Membrane Composition
- 55% protein
- 40% lipids
- 5% carbohydrates
Cell Membrane Lipids
- Phospholipids: arranged in a bilayer
- Cholesterol: between the phospholipids
Cell Membrane Proteins
- Integral proteins: span the membrane
- Peripheral proteins: located on the surface
Ion Channels
- Integral membrane proteins
- Allow specific ions to pass across the membrane
- Controlled by gates (can open or close)
- Can be chemically or electrically gated
Carbohydrates
- Attached to proteins (glycoproteins) or lipids (glycolipids)
- Carry negative charges
- Important for cell-cell recognition and adhesion
Cellular Junctions
- Tight, gap, and anchoring junctions
- Cell-to-cell connections
- Enable communication between cells and/or prevent substance passing between cells
Transport Mechanisms Across the Cell Membrane
- Passive transfer (no energy required): diffusion, osmosis, facilitated diffusion
- Active transport (needs energy): primary active and secondary active
Passive Transport
- Simple diffusion (e.g., gases)
- Facilitated diffusion (e.g., glucose, ions through channels)
- Osmosis (water movement across a semipermeable membrane)
Active Transport
- Primary active transport (directly uses ATP): Na+/K+-ATPase pump
- Secondary active transport (uses a concentration gradient generated by primary active transport): Cotransport (symport) and countertransport (antiport)
Vesicular Transport
- Endocytosis (e.g., phagocytosis, pinocytosis)
- Exocytosis (e.g., releasing hormones, neurotransmitters)
Filtration
- Process of forcing a fluid through a semipermeable membrane by applying pressure.
- Important in the kidneys for urine formation.
Nerve Cells (Neurons)
- Components: cell body (soma), dendrites, axon.
- Function: transmit nerve impulses.
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Description
Explore the intricate details of human body composition, including the distribution of water, solids, and the roles of intracellular and extracellular fluids. This quiz covers calculations of total body water, fluid composition, and important physiological concepts such as pH and osmolarity. Test your understanding of these essential biological concepts!
