NUR1112 - Fundamental Skills and Knowledge for Nursing and Midwifery Practice

Anatomy and Physiology

• Anatomy: Study of body structures.
• Physiology: Study of body functions.
• Anatomy and physiology are interrelated; structure determines function.

Levels of Human Structure (Simplest to Most Complex)

• Chemical Level:
  • Atoms: Basic units of matter (e.g., Oxygen (O), Hydrogen (H)).
  • Molecules: Two or more atoms bonded together.
  • Macromolecules: Large molecules (e.g., proteins, nucleic acids).
  • Organelles: Functional units within cells (e.g., mitochondrion, nucleus).
• Microscopic Level:
  • Cell: Basic structural and functional unit of the body.
  • Tissues: Groups of similar cells performing a specific function.
• Macroscopic Level:
  • Organ: A structure composed of two or more tissue types performing a specific function.
  • Organ System: A group of organs working together to perform a common function.
  • Organism: The complete living being.

Organ Systems and Their Major Functions

• Functional Integration: All body cells are interdependent and work together to maintain life functions.
• Digestive System: Takes in nutrients, breaks them down, and eliminates unabsorbed matter (feces).
• Respiratory System: Takes in oxygen (O₂) and eliminates carbon dioxide (CO₂).
• Cardiovascular System: Distributes oxygen and nutrients to body cells and delivers wastes and carbon dioxide to disposal organs via the blood.
• Urinary System: Eliminates nitrogenous wastes and excess ions (urine).
• Integumentary System: Protects the body from the external environment.
• Interstitial Fluid: Nutrients and wastes pass between blood and cells via the interstitial fluid.

Internal Environment and Fluid Compartments

• Internal Environment: Consists of cells suspended in fluid.
  • Intracellular Fluid (ICF): Fluid inside the cells.
  • Extracellular Fluid (ECF): Fluid outside the cells, including interstitial fluid (ISF) and plasma.
• Body Fluid Compartments:
  • Total Body Water: $60\%$ of body weight (approximately $40$ L).
  • Intracellular Fluid (ICF): $40\%$ of body weight (approximately $25$ L).
  • Extracellular Fluid (ECF): $20\%$ of body weight (approximately $15$ L).
    • Plasma: $20\%$ of ECF (approximately $3$ L).
    • Interstitial Fluid (IF): $80\%$ of ECF (approximately $12$ L).

Composition of Body Fluids

• Body fluids (ECF, ICF) are solutions.
• Solutions = Solvent + Solute(s).
  • Solvent: Water.
  • Solutes: Components dissolved in the solvent (e.g., O₂, CO₂, K⁺, Na⁺).

Atoms, Molecules, Chemical Reactions, and Enzymes

• Elements: Substances in which all particles are the same (e.g., Oxygen (O), Hydrogen (H)).

Element Composition of the Human Body

• Major Elements (96.1% of body mass):
  • Oxygen (O): $65.0\%$. Atomic symbol: O
  • Carbon (C): $18.5\%$. Atomic symbol: C
  • Hydrogen (H): $9.5\%$. Atomic symbol: H
  • Nitrogen (N): $3.2\%$. Atomic symbol: N
• Lesser Elements (3.9% of body mass):
  • Calcium (Ca): $1.5\%$. Atomic symbol: Ca
  • Phosphorus (P): $1.0\%$. Atomic symbol: P
  • Potassium (K): $0.4\%$. Atomic symbol: K
  • Sulfur (S): $0.3\%$. Atomic symbol: S
  • Sodium (Na): $0.2\%$. Atomic symbol: Na
  • Chlorine (Cl): $0.2\%$. Atomic symbol: Cl
  • Magnesium (Mg): $0.1\%$. Atomic symbol: Mg
  • Iodine (I): $0.1\%$. Atomic symbol: I
  • Iron (Fe): $0.1\%$. Atomic symbol: Fe
• Trace Elements: < $0.01\%$, e.g., copper, fluorine, zinc.

Atoms and Molecules

• Atoms: Smallest units of elements.
• Molecules: Formed from two or more atoms bound together.
• Macromolecules: Very large molecules.
• Molecular Formula: Identifies elements and number of atoms.

Chemical Reactions

• Chemical Reactions: Occur when substances are chemically changed into new substances. Example: $2H + O \rightarrow H_2O$
• Types of Chemical Reactions:
  • Synthesis/Anabolic: Small molecules combine to form larger ones.
  • Decomposition/Catabolic: Large molecules break down into smaller ones.
  • Exchange/Displacement: Chemical bonds are both made and broken.

Enzymes

• Enzymes: Biological catalysts that speed up the rate of a reaction.
  • Protein molecules.
  • Not consumed during the process.
  • Highly specific.

Organic vs. Inorganic Molecules

• Organic Molecules:
  • Larger and more complex.
  • Contain both carbon (C) and hydrogen (H).
  • Typically insoluble in water.
  • Macromolecules: Carbohydrates, lipids, proteins, nucleic acids.
• Inorganic Molecules:
  • Simpler.
  • Do not contain both carbon (C) and hydrogen (H) (e.g., CO₂).
  • Typically soluble in water.
  • Ions.

Ions and Electrolytes

• Atoms are electrically neutral.
• Cations: Positive charge.
  • Hydrogen ion (H⁺)
  • Sodium ion (Na⁺)
  • Potassium ion (K⁺)
  • Calcium ion (Ca²⁺)
• Anions: Negative charge.
  • Chloride ion (Cl⁻)
  • Hydroxide ion (OH⁻)
  • Bicarbonate ion (HCO₃⁻)
• Electrolytes: Substances that release ions in water.

Electrolytes and Their Functions

• Essential for normal body functioning.
  • Sodium ions (Na⁺): Water balance and normal cell functions.
  • Potassium ions (K⁺): Water balance and normal cell functions.
  • Calcium ions (Ca²⁺): Nerve and muscle function.
  • Magnesium ions (Mg²⁺): Nerve and muscle function.

Electrolytes: Acids, Bases, and Salts

• Acids: Release H⁺ ions (more acidic).
• Bases: Release ions that bind H⁺ (less acidic).
• Salts: Release ions other than H⁺ or OH⁻ (no change to acidity).

pH Scale

• pH = “power of Hydrogen”.
• Solutions with higher H⁺ concentrations are more acidic.
• Solutions with lower H⁺ concentrations are more basic/alkaline.
• Neutral: $H^+ = OH^-$

Plasma pH

• Living cells are sensitive to changes in pH.
• Normal plasma pH range: $7.35 - 7.45$
• Plasma pH < $7.35$: Acidosis.
• Plasma pH > $7.45$: Alkalosis.

Macromolecules

• Macromolecules are polymers—chain-like molecules made of similar or repeating units called monomers.
• Four classes of macromolecules:
  • Carbohydrates
  • Lipids
  • Nucleic acids
  • Proteins

Carbohydrates

• Contain carbon, hydrogen, and oxygen (e.g., glucose $C<em>6H</em>{12}O_6$).
• Building blocks: monosaccharides (simple sugars).
• Types:
  • Monosaccharides: Single monomer (e.g., glucose).
  • Disaccharides: Two monomers (e.g., sucrose, lactose).
  • Polysaccharides: Many monomers (e.g., glycogen).
• Function: Provide energy for cellular function; glycogen for storage.

Lipids

• Types:
  • Triglycerides
  • Phospholipids
  • Steroids
• Triglycerides building blocks: fatty acids and glycerol.
• Functions:
  • Long-term energy storage
  • Thermal insulation
  • Protection from mechanical trauma

Lipids: Phospholipids

• Hydrophilic (“water-loving”) head.
• Hydrophobic (“water-fearing”) tails.
• Function: Phospholipid bilayers form all cell membranes.

Lipids: Steroids

• Flat molecules of four interlocking hydrocarbon rings.
• Functions:
  • Cholesterol: Essential for cell membranes.
  • Hormones: Chemical messengers that regulate physiological processes.
  • Vitamin D: Essential for bone growth.
  • Bile salts: Aids in fat digestion.

Nucleic Acids

• Largest molecules in our body.
• Types:
  • Deoxyribonucleic acid (DNA)
  • Ribonucleic acid (RNA)
• Building blocks: Nucleotides (phosphate group, ribose sugar, nucleotide base).

Nucleic Acids: DNA

• Functions:
  • Hereditary information.
  • Provides instructions for building every protein in the body.
  • A gene is a span of DNA with instructions for building one protein.
• DNA is a double helix formed from two strands of nucleotides.

Nucleic Acids: RNA

• RNA is a single strand of nucleotides.
• Functions: Carries out the task of protein synthesis as instructed by DNA.
• Example: ATP (Adenosine triphosphate) – adenosine nucleotide with two extra phosphates; an easily accessible energy source.
  Breaking phosphate bonds releases energy for cellular functions.

Proteins

• Building blocks: Amino acids.
• Protein structure determines its function.
• Structural classifications:
  • Fibrous proteins
  • Globular proteins
• Protein structure is determined by:
  • Identity and sequence of amino acids
  • How the amino acid string is folded (3-dimensional shape)

Proteins: Fibrous vs. Globular

• Fibrous:
  • Elongated and strand-like.
  • Stable.
  • Major building material in the body; provides mechanical support and tensile strength.
  • e.g., keratin, collagen.
• Globular:
  • Compact and spherical.
  • Chemically active.
  • Crucial in biological processes.
  • e.g., hormones, enzymes.

Proteins: Denaturation

• Any change in structure/shape can alter or destroy protein function (denaturation).
• The function of every cell (and, therefore, tissue/organ/system) is dependent on proteins.
• The body must maintain stable internal conditions to prevent protein denaturation.
• Changes in the internal environment can cause denaturation (pH, temperature).

Homeostasis

• Cell survival depends on maintaining internal conditions within a normal range.

Cell Survival and the Internal Environment

• Internal conditions within normal range are essential for normal cell function.

Regulation of Internal Environment

• Cells, tissues, organs, and organ systems work together to maintain the internal environment.

Variables Regulated in the Internal Environment

• Gas concentrations
• Nutrient levels
• Water volume
• Electrolyte concentrations (e.g., Na⁺, K⁺, Ca²⁺ ions)
• Acid-base balance (H⁺ ions)
• Temperature
• Waste products
  Variables within the ECF should be kept within a narrow range.

Homeostasis

• Homeostasis is the process that leads to relatively stable conditions in the internal environment.
  • "Homeo" = the same/similar
  • "Stasis" = condition
• Conditions are constantly fluctuating.
• Homeostatic control mechanisms are used to keep conditions within their homeostatic range.

Homeostatic Control Mechanism

• Stimulus: Change in variable outside its normal range.
• Receptor: Detects stimulus.
• Afferent pathway: Transmits information from receptor to control center (nerve impulses or hormones).
• Control center: Analyzes the stimulus, decides on response, and directs the effector.
• Efferent pathway: Transmits information from control center to effector (nerve impulses or hormones).
• Effector: Elicits the response.
• Response: Acts on the variable.

Feedback Loops

• Negative Feedback: Reduces the stimulus and restores the variable to within the normal range.
• Positive Feedback: Amplifies the stimulus and keeps the variable outside the normal range; ends with a product/endpoint.

Negative Feedback Loop Example

• Stimulus: Increase in body temperature.
• Receptor: Thermoreceptors.
• Control center: Brain.
• Effector: Blood vessels and sweat glands.
• Response: Vasodilation and sweating leading to a decrease in temperature.

Positive Feedback Loop Example

• Stimulus: Stretching of the cervix.
• Receptor: Mechanoreceptors.
• Control center: Brain.
• Effector: Uterus.
• Response: Uterine contractions leading to increased stretching of the cervix.

Blood

• Blood is a fluid connective tissue.

Composition of Blood

• Plasma: 55% of total blood volume.
  • Mostly water.
  • Dissolved solutes.
  • Plasma proteins.
• Buffy Coat: <1% of total blood volume.
  • Leukocytes (white blood cells).
  • Platelets.
• Haematocrit: % of total blood volume that is RBCs (red blood cells).
  • 47 ± 5% for males.
  • 42 ± 5% for females.
  • Average 45%.

Erythrocytes (RBCs)

• Structure enables gas transport.
  • Biconcave shape: Stackable and large surface area relative to volume.
  • No organelles: More space for haemoglobin (protein that binds O₂ and some CO₂).
  • Flexible: Ability to bend.

Functions of Blood

• Distribution:
  • O₂ and nutrients (e.g., glucose).
  • Waste removal (e.g., CO₂).
  • Hormones.
• Regulation:
  • pH.
  • Body temperature.
  • Interstitial fluid (e.g., electrolytes).
• Protection:
  • Infection control.
  • Prevention of blood loss.

Blood and Homeostasis

• The functions of blood are essential for maintaining the conditions of the internal environment within normal limits so that homeostasis can be maintained.

Homeostasis and Protein Denaturation

• Homeostasis is ultimately about preventing protein denaturation so that all levels of structure can function properly.