🩺Biomedical Instrumentation Unit 2 – Human Physiology and Anatomy Fundamentals

Key Anatomical Structures

• Human body organized into various levels of complexity includes cells, tissues, organs, and systems
• Skeletal system provides structural support and protection for internal organs (skull, ribcage, vertebral column)
• Muscular system enables movement and maintains posture through contraction of skeletal, smooth, and cardiac muscle tissues
  • Skeletal muscle attaches to bones via tendons and facilitates voluntary movements (biceps, quadriceps)
  • Smooth muscle found in walls of hollow organs and blood vessels enables involuntary movements (peristalsis, vasoconstriction)
  • Cardiac muscle found exclusively in the heart and facilitates pumping of blood throughout the body
• Nervous system consists of the brain, spinal cord, and network of nerves that transmit signals to coordinate body functions
  • Central nervous system (CNS) includes the brain and spinal cord, processes information and generates responses
  • Peripheral nervous system (PNS) consists of nerves that connect the CNS to the rest of the body, relaying sensory and motor information
• Circulatory system transports blood, nutrients, oxygen, and waste products throughout the body
  • Heart serves as the central pump, propelling blood through a network of arteries, capillaries, and veins
  • Blood composed of plasma, red blood cells (oxygen transport), white blood cells (immune defense), and platelets (clotting)
• Respiratory system facilitates gas exchange between the environment and the bloodstream (lungs, trachea, bronchi, alveoli)
• Digestive system breaks down food into absorbable nutrients and eliminates waste products (mouth, esophagus, stomach, intestines, liver, pancreas)
• Urinary system filters blood, maintains fluid and electrolyte balance, and removes metabolic waste (kidneys, ureters, bladder, urethra)

Physiological Systems Overview

• Integumentary system serves as a protective barrier, regulates body temperature, and facilitates sensory perception (skin, hair, nails, sweat glands)
• Endocrine system consists of glands that secrete hormones to regulate various body functions (pituitary, thyroid, adrenal, pancreas)
  • Hormones are chemical messengers that travel through the bloodstream to target specific cells or organs
  • Endocrine glands secrete hormones directly into the bloodstream, while exocrine glands secrete substances through ducts (sweat, saliva, digestive enzymes)
• Lymphatic system plays a crucial role in immune defense and fluid balance (lymph nodes, lymph vessels, spleen, thymus)
  • Lymph is a clear fluid that collects excess interstitial fluid and returns it to the bloodstream
  • Lymph nodes filter lymph and trap pathogens and foreign substances, activating immune responses
• Reproductive system ensures the production of gametes and the perpetuation of the species (testes, ovaries, uterus, vagina, penis)
• Sensory systems allow the body to perceive and respond to external stimuli (vision, hearing, taste, smell, touch, proprioception)
• Immune system defends the body against pathogens and foreign substances through a complex network of cells, tissues, and organs
  • Innate immunity provides immediate, non-specific defense mechanisms (skin, mucous membranes, inflammatory response)
  • Adaptive immunity develops specific, long-lasting protection through the action of lymphocytes (B cells, T cells) and antibodies

Homeostasis and Regulation

• Homeostasis refers to the maintenance of a stable internal environment despite changes in the external environment
• Negative feedback loops are the primary mechanism for maintaining homeostasis
  • Deviations from the set point trigger compensatory responses to restore balance (thermoregulation, blood glucose regulation)
  • Receptors detect changes in the internal environment and send signals to the control center (hypothalamus, pancreas)
  • Effectors carry out the necessary adjustments to return the system to its set point (sweat glands, insulin secretion)
• Positive feedback loops amplify the initial stimulus and are less common in the body (blood clotting, uterine contractions during childbirth)
• Hormonal regulation involves the secretion of hormones by endocrine glands to control various physiological processes
  • Hormones bind to specific receptors on target cells, triggering intracellular signaling cascades
  • Examples include insulin regulating blood glucose levels and thyroid hormones regulating metabolism
• Neural regulation involves the transmission of electrical signals through the nervous system to coordinate body functions
  • Neurons communicate via synapses, releasing neurotransmitters that bind to receptors on the postsynaptic cell
  • Examples include the autonomic nervous system regulating heart rate, blood pressure, and digestion
• Homeostatic imbalances can lead to various pathological conditions (hypertension, diabetes, hypothyroidism)

Cell and Tissue Biology

• Cells are the basic structural and functional units of life
  • Eukaryotic cells contain membrane-bound organelles (nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus)
  • Prokaryotic cells lack membrane-bound organelles and have a simpler structure (bacteria)
• Cell membrane is a selectively permeable barrier that regulates the passage of molecules in and out of the cell
  • Composed of a phospholipid bilayer with embedded proteins (channels, receptors, enzymes)
  • Passive transport occurs down the concentration gradient without energy input (diffusion, osmosis)
  • Active transport requires energy input to move molecules against the concentration gradient (sodium-potassium pump)
• Tissues are groups of cells with similar structure and function that work together to perform a specific role
  • Epithelial tissue covers body surfaces and lines hollow organs, providing protection and facilitating absorption and secretion
  • Connective tissue supports and connects other tissues, including bone, cartilage, blood, and adipose tissue
  • Muscle tissue enables movement through contraction and includes skeletal, smooth, and cardiac muscle
  • Nervous tissue transmits electrical signals and includes neurons and glial cells
• Cell division is the process by which cells reproduce, replacing damaged or lost cells and facilitating growth and repair
  • Mitosis results in the production of two genetically identical daughter cells (somatic cells)
  • Meiosis produces four genetically diverse haploid gametes (sperm, egg) for sexual reproduction
• Cellular metabolism encompasses the chemical reactions that occur within cells to maintain life
  • Catabolism breaks down complex molecules to release energy (cellular respiration, beta-oxidation)
  • Anabolism uses energy to synthesize complex molecules from simpler ones (protein synthesis, lipogenesis)

Bioelectric Signals in the Body

• Bioelectric signals are electrical potentials generated by the activity of excitable cells (neurons, muscle cells)
• Resting membrane potential is the electrical potential difference across the cell membrane when the cell is at rest
  • Maintained by the unequal distribution of ions (primarily sodium and potassium) across the membrane
  • Typically around -70 mV in neurons, with the inside of the cell more negative than the outside
• Action potentials are rapid, transient changes in the membrane potential that propagate along the cell membrane
  • Triggered when the membrane potential reaches a threshold value, causing voltage-gated sodium channels to open
  • Depolarization occurs as sodium ions rush into the cell, making the inside more positive
  • Repolarization follows as potassium ions exit the cell, restoring the resting membrane potential
• Synaptic transmission is the process by which neurons communicate with each other or with effector cells (muscle, gland)
  • Electrical synapses allow direct transmission of electrical signals between cells via gap junctions
  • Chemical synapses involve the release of neurotransmitters from the presynaptic neuron, which bind to receptors on the postsynaptic cell
• Electroencephalography (EEG) measures the electrical activity of the brain by recording voltage fluctuations on the scalp
  • Reflects the summated activity of millions of neurons in the cerebral cortex
  • Used to diagnose and monitor neurological conditions (epilepsy, sleep disorders, brain tumors)
• Electrocardiography (ECG) records the electrical activity of the heart, providing information about heart rate, rhythm, and function
  • Measures the depolarization and repolarization of the atria and ventricles during the cardiac cycle
  • Used to diagnose and monitor cardiovascular conditions (arrhythmias, myocardial infarction, conduction abnormalities)

Measurement Techniques and Instrumentation

• Biomedical instrumentation involves the application of engineering principles to measure and analyze physiological signals
• Sensors and transducers convert physiological signals into electrical signals that can be processed and analyzed
  • Electrodes are used to measure bioelectric signals (EEG, ECG, EMG)
  • Pressure sensors measure changes in pressure (blood pressure, intracranial pressure)
  • Temperature sensors measure changes in temperature (core body temperature, skin temperature)
  • Optical sensors measure changes in light absorption or emission (pulse oximetry, near-infrared spectroscopy)
• Signal conditioning involves the amplification, filtering, and digitization of raw signals to improve signal quality and facilitate analysis
  • Amplifiers increase the amplitude of weak signals to a level suitable for further processing
  • Filters remove unwanted noise and interference, isolating the desired frequency components
  • Analog-to-digital converters (ADCs) convert continuous analog signals into discrete digital values for computer processing
• Data acquisition systems (DAQ) are used to collect, store, and display physiological data
  • Typically consist of a computer, software, and hardware interfaces for connecting sensors and transducers
  • Allow real-time monitoring, analysis, and visualization of physiological signals
• Imaging techniques provide non-invasive visualization of anatomical structures and physiological processes
  • X-ray radiography uses ionizing radiation to create 2D images of dense structures (bones, lungs)
  • Computed tomography (CT) uses X-rays to generate cross-sectional images of the body
  • Magnetic resonance imaging (MRI) uses strong magnetic fields and radio waves to create detailed images of soft tissues
  • Ultrasound uses high-frequency sound waves to visualize internal structures and monitor blood flow

Clinical Applications and Diagnostics

• Biomedical instrumentation plays a crucial role in the diagnosis, monitoring, and treatment of various medical conditions
• Cardiovascular diagnostics involve the assessment of heart function and blood flow
  • ECG is used to diagnose arrhythmias, myocardial infarction, and conduction abnormalities
  • Echocardiography uses ultrasound to visualize the heart's structure and function
  • Cardiac catheterization involves the insertion of a catheter into the heart to measure pressures and assess coronary artery disease
• Respiratory diagnostics assess lung function and gas exchange
  • Spirometry measures lung volumes and airflow rates to diagnose conditions like asthma and COPD
  • Pulse oximetry non-invasively measures the oxygen saturation of the blood
  • Capnography measures the concentration of carbon dioxide in exhaled air to monitor ventilation and perfusion
• Neurological diagnostics evaluate the structure and function of the nervous system
  • EEG is used to diagnose epilepsy, sleep disorders, and brain tumors
  • Electromyography (EMG) measures the electrical activity of muscles to diagnose neuromuscular disorders
  • Evoked potential studies assess the integrity of sensory pathways (visual, auditory, somatosensory)
• Endocrine diagnostics involve the measurement of hormone levels to evaluate endocrine function
  • Blood tests are used to measure levels of hormones like thyroid stimulating hormone (TSH), cortisol, and insulin
  • Glucose tolerance tests assess the body's ability to regulate blood sugar levels and diagnose diabetes
• Genetic diagnostics use molecular techniques to identify genetic mutations and predispositions to disease
  • Polymerase chain reaction (PCR) amplifies specific DNA sequences for analysis
  • DNA sequencing determines the precise order of nucleotides in a DNA molecule
  • Microarrays allow the simultaneous analysis of thousands of genes or genetic variants

Ethical Considerations in Biomedical Research

• Biomedical research must adhere to ethical principles to protect the rights and welfare of human subjects
• Informed consent is a fundamental requirement for human subjects research
  • Participants must be fully informed about the nature, risks, and benefits of the study
  • Consent must be voluntary and free from coercion or undue influence
  • Special considerations apply for vulnerable populations (children, mentally impaired, prisoners)
• Privacy and confidentiality must be maintained throughout the research process
  • Personal and medical information must be securely stored and accessed only by authorized personnel
  • Data should be anonymized or de-identified to protect participant privacy
• Risks and benefits must be carefully balanced to ensure that the potential benefits justify the risks
  • Research should aim to minimize risks and maximize benefits to participants and society
  • Animal research must follow ethical guidelines to minimize suffering and ensure humane treatment
• Conflicts of interest must be disclosed and managed to maintain the integrity of the research
  • Financial or personal interests that could influence the design, conduct, or reporting of the study must be declared
  • Institutional review boards (IRBs) oversee the ethical conduct of research and ensure compliance with regulations
• Social and cultural considerations must be taken into account, particularly when conducting research in diverse populations
  • Research should be sensitive to the values, beliefs, and practices of the communities involved
  • Community engagement and collaboration can help build trust and ensure the relevance and acceptability of the research
• Responsible conduct of research involves adhering to principles of honesty, objectivity, and transparency
  • Data should be accurately recorded, analyzed, and reported, with any limitations or uncertainties acknowledged
  • Authorship and publication practices should follow established guidelines and give credit where due
  • Misconduct, such as fabrication, falsification, or plagiarism, undermines the integrity of the research enterprise and must be avoided