Comprehensive Guide to Human Biology and Physiology
Human Biology and Physiology
Macromolecules
Carbohydrates
Energy source, structural components
Proteins
Enzymes, transport, support, motion, regulation
Lipids
Energy storage, insulation, cell membranes.
Nucleic Acids
DNA/RNA, genetic information storage and transfer.
Enzymes
Biological catalysts that speed up biochemical reactions without being consumed. Specific to substrates; function influenced by temperature, pH, and concentration.
Metabolic Pathways
Anabolic Pathways
Synthesize complex molecules from simpler ones (e.g., protein synthesis).
Catabolic Pathways
Break down complex molecules into simpler ones (e.g., cellular respiration)
Cell Structure and Function
Nucleus
Contains genetic material (DNA), controls cell activities.
Mitochondria
Powerhouse of the cell, ATP production.
Ribosomes
Protein synthesis.
Endoplasmic Reticulum
Rough ER
Protein synthesis and processing.
Smooth ER
Lipid synthesis, detoxification
Golgi Apparatus
Modifies, sorts, and packages proteins and lipids for storage or transport.
Cell Membrane
Phospholipid bilayer with embedded proteins; selective permeability. Transport mechanisms:
Tissues
Epithelial
Covers body surfaces, lines cavities, forms glands (functions: protection, absorption, secretion)
Connective
Supports, protects, binds other tissues (types: bone, blood, adipose, cartilage).
Muscle
Responsible for movement (types: skeletal, cardiac, smooth).
Nervous
Transmits electrical impulses, processes information (neurons, glial cells)
Homeostasis
Negative Feedback
Reduces output to maintain stability (e.g., body temperature regulation).
Positive Feedback
Enhances output for a specific outcome (e.g., childbirth contractions).
Organ Systems
Endocrine System
Hormone regulation (e.g., insulin/glucagon for blood glucose levels).
Nervous System
Rapid response via nerve impulses.
Skeletal System
Bones, cartilage, ligaments.
Functions
- Support: Framework for body.
- Protection: Shields vital organs (e.g., skull protects brain).
- Movement: Levers for muscles to act upon.
- Mineral Storage: Reservoir for calcium and phosphorus.
- Blood Cell Production: Hematopoiesis in bone marrow.
Bone Types
- Long (femur)
- Short (carpals)
- Flat (sternum)
- Irregular (vertebrae)
Joint Types
- Fibrous: Immovable (e.g., sutures of the skull).
- Cartilaginous: Slightly movable (e.g., intervertebral discs).
- Synovial: Freely movable (e.g., knee, elbow).
Muscular System
Types of Muscle Tissue
- Skeletal Muscle: Voluntary movement, striated.
- Cardiac Muscle: Involuntary, striated, found in the heart.
- Smooth Muscle: Involuntary, non-striated, found in walls of internal organs.
Functions
- Movement: Contraction of muscles pulls on bones.
- Posture: Stabilizes body position.
- Heat Production: Muscle activity generates heat.
Muscle Contraction
- Sliding Filament Theory: Actin and myosin filaments slide past each other.
- Neuromuscular Junction: Synapse between motor neuron and muscle fiber; acetylcholine release triggers muscle contraction.
Nervous System
Neuron Components
- Cell Body (Soma): Contains nucleus, metabolic center
- Dendrites: Receive signals.
- Axon: Transmits signals away.
- Synapses: Junctions between neurons.
Types of Neurons
- Sensory Neurons: Carry impulses to CNS.
- Motor Neurons: Carry impulses from CNS to effectors.
- Interneurons: Connect neurons within CNS.
Neuronal Pathways
- Action Potential: Electrical signal that travels along neurons.
- Resting Membrane Potential: -70mV, maintained by Na+/K+ pump.
- Depolarization: Na+ influx.
- Repolarization: K+ efflux.
- Hyperpolarization: Temporary excess K+ outflow.
Synaptic Transmission
- Neurotransmitter Release: From presynaptic neuron
- Synaptic Cleft: Space neurotransmitters cross.
- Receptor Binding: On postsynaptic neuron.
Central Nervous System (CNS)
- Brain:
- Cerebrum: Higher functions (thinking, memory).
- Cerebellum: Coordination of movement.
- Brainstem: Basic life functions (breathing, heart rate).
- Spinal Cord: Transmits signals between brain and body.
Peripheral Nervous System (PNS)
- Somatic Division: Voluntary control of skeletal muscles.
- Autonomic Division: Involuntary control (sympathetic and parasympathetic systems).
Sensory, Integrative, and Responsive Functions
- Sensory Pathways: Sensory receptors → afferent neurons → CNS.
- Integrative Functions: CNS processing and interpretation of sensory information.
- Responsive Pathways: CNS → efferent neurons → effectors (muscles, glands).
Other Organ Systems and Their Functions
- Cardiovascular and Respiratory Systems: Oxygen delivery to tissues, removal of carbon dioxide. Example: COPD, asthma.
- Digestive and Excretory Systems: Nutrient absorption, waste elimination. Example: Chronic kidney disease, diabetes.
- Endocrine and Nervous Systems: Hormonal regulation, neural control. Example: Hypothyroidism, multiple sclerosis.
Case Study Application
- Approach:
- Identify affected systems.
- Understand underlying pathology.
- Propose evidence-based interventions.
- Examples:
- Diabetes: Insulin regulation, blood glucose levels, complications (neuropathy, retinopathy).
- Osteoporosis: Bone density loss, calcium and vitamin D role, fracture risk.
- Muscular Dystrophy: Genetic mutations affecting muscle proteins, progressive muscle weakness