Cellular Biology & Neurological System Week 1 & 2 Notes PDF

Created by Turbolearn AI Cellular Biology & Neurological System: Week 1 & 2 Notes 1.1 Cellular Biology ‍ Cells, Tissues, and Organs Cells: Basic units of life. Tissues: Groups of cells with common structure and function (muscle, neural, epithelial, connective). Organs: Different ti...

Created by Turbolearn AI Cellular Biology & Neurological System: Week 1 & 2 Notes 1.1 Cellular Biology ‍ Cells, Tissues, and Organs Cells: Basic units of life. Tissues: Groups of cells with common structure and function (muscle, neural, epithelial, connective). Organs: Different tissues working together for a specific function (heart, brain, kidneys). Cellular Functions Function Description Example Muscle cells generate force Limb movement, colon Movement producing motion. contraction Response to stimulus via wave of Conductivity Nerve cells (brain, heart) excitation (electrical potential). Metabolic Cells take in and use nutrients. Cells of intestines or kidneys Absorption Cells synthesize and secrete new Secretion Mucous gland cells substances. Lysosomes break down Excretion Cells remove waste products. molecules, waste released Cells use oxygen to transform Glucose oxidation in Respiration nutrients into ATP (energy). mitochondria Cells enlarge and reproduce for Reproduction Mitosis, meiosis tissue growth and maintenance. Cells communicate to maintain a Communication Cell signaling dynamic steady state. Page 1  Created by Turbolearn AI Plasma Membranes Define the cell's boundaries. Allow or exclude various molecules via selective transport. Influence metabolic pathways. Important for cell-to- cell recognition, cellular mobility, and maintaining cellular shape. Membrane functions are largely determined by proteins: Recognition and binding units (receptors). Pores or transport channels. Enzymes driving active pumps. Cell surface markers (glycoproteins). Cell adhesion molecules. Catalysts of chemical reactions. Cellular Components Nucleus: Largest membrane-bound organelle; controls cell division and genetic information (DNA replication, repair, transcription to RNA). Mitochondria: Numerous in most cells; responsible for cellular respiration and ATP (energy) production. Ribosomes: Sites of protein synthesis; proteins are the major workhorses of the cell, moving via gated transport, protein translocation, or vesicular transport. Cellular Adaptation Normal cells adapt to stress (atrophy, hypertrophy, hyperplasia, metaplasia). Injury occurs if adaptation is exceeded. Mild injury is reversible; persistent stimuli cause irreversible injury and death. Atrophy: Decrease in cell size. Hypertrophy: Increase in cell size. Hyperplasia: Increase in cell number. Metaplasia: Reversible replacement of one cell type by another (e.g., squamous metaplasia in smokers' lungs). Dysplasia: Atypical hyperplasia (not a true adaptation). Page 2  Created by Turbolearn AI Hypoxia Cells lack sufficient oxygen; the most common cause of cellular injury. Ischemia (reduced blood supply) is the most common cause of hypoxia. Negatively impacts all normal cellular functions. Causes of Hypoxia: Reduced oxygen in air. Loss of hemoglobin. Decreased red blood cell production. Respiratory and cardiovascular diseases. Poisoning of cellular oxidative enzymes. Consequences of Hypoxia: Negative impact on normal processes (differentiation, angiogenesis, proliferation, erythropoiesis, cell viability). Mitochondria produce reactive oxygen species (ROS), leading to oxidative stress and cell damage. ROS is a component of inflammation. Hypoxia and inflammation are linked to various diseases (IBD, certain cancers, infections). Oxidative stress damages proteins, lipids, and nucleic acids. Oxidative stress activates intracellular signaling pathways. Antioxidants protect cells against free radicals. 2.1 Neurological System: Brain Anatomy & Function Hypothalamus Image source: https://www.hopkinsmedicine.org/health/conditions-and- diseases/anatomy-of-the-brain Functions (Mnemonic: AS-CEPSTER): Page 3  Created by Turbolearn AI Function Description Autonomic Functions Controls the autonomic nervous system. Sleep-Wake Cycle Regulates sleep and wakefulness. Circadian Rhythm Control Regulates the body's internal clock. Endocrine Functions Controls hormone release from the pituitary gland. Food Intake (appetite) Regulates hunger and satiety. Sexual Behavior Plays a role in sexual behavior and reproduction. Temperature Regulation Maintains body temperature. Emotional & Instinctual Involved in emotional responses and instinctive Behavior behaviors. Reward & Punishment Center Processes feelings of reward and punishment. Major sleep center in the brain: Hypothalamus Pain Pain is whatever the person says it is (subjective). A complex process involving afferent (ascending) and efferent (descending) pathways with interpretive centers. Pain threshold: Lowest intensity at which pain is perceived. Pain tolerance: Highest intensity a person can tolerate. Acute pain: Short duration. Chronic pain: >3 months. Signs and Symptoms of Pain: Increased heart rate & respiratory rate. Hypertension. Diaphoresis. Dilated pupils. In children: Facial expressions, body rigidity, crying, sleep disorders, resistance to touch. Fever Page 4  Created by Turbolearn AI Fever is triggered by pyrogens (from leukocytes, other cells, and bacteria). It's both a symptom and a normal immunologic mechanism. Involves resetting the hypothalamic thermostat. Fever's Role in Healing: Increased temperature kills pathogens. Decreases serum iron, zinc, and copper (needed for bacterial replication). Causes lysosomal breakdown and cell destruction. Prevents viral replication. Enhances immune response (lymphocytic transformation, neutrophil motility, phagocytosis, interferon production). Febrile Seizures May occur in children with temperature > 38°C (100.4°F) without CNS infection, hypoglycemia, or electrolyte disorders. More common in boys