General Sensation and Cardiovascular Dynamics Lab

Sensory Modality

• Achieved through specialized receptors that detect specific stimuli (light, sound, touch, etc.) and convert them into electrical signals sent to the brain via neural pathways
• Brain processes these signals and perceives them as different senses

Cutaneous Sense Lab Activities

• Pressure sensation test
• Two-point discrimination test
• Touch localization test

Cutaneous Receptors

• Nocireceptors
• Thermoreceptors
• Mechanoreceptors

Receptor Conversion

• Receptors convert diverse physical stimuli into electrical signals through transduction
• Involves sensory transduction by a nerve cell and an epithelial cell

Referred Pain

• Pain that occurs in internal organs but is sensed on the body surface (e.g., brain freeze)

Types of Sensory Receptors

• Chemoreceptors
• Photo Receptors
• Thermoreceptors
• Mechanoreceptors
• Electromagnetic receptors

Cardiovascular Dynamics

• CO formula (cardiac output): measures the amount of blood pumped into each ventricle (ml/min)
• SV formula (stroke volume): measures the amount of blood ejected from the ventricle with each cardiac cycle (ml/beat)
• Poiseuille's Law: describes the volume rate of flow in terms of fluid viscosity, $Q=(P2-P1)\pi r^4 / 8 \eta l $

Factors Affecting Stroke Volume (SV)

• Radius
• Length

Cardiovascular Diseases

• Hypertension
• Stroke
• Congenital heart defect
• Heart failure
• Coronary heart disease
• Aortic aneurysm

Pain Control

• Body controls pain through a complex process involving the nervous system
• Pain signals are detected by nociceptors and sent to the brain via the spinal cord
• Brain processes these signals and can modulate pain perception using neurotransmitters and endorphins

Blood Composition

• Plasma makes up approximately 55% of blood, consisting of 92% water, 7% proteins, and 1% nutrients, hormones, gases, and waste products
• Proteins in blood plasma include albumin, globulins, and fibrinogen, with albumin being the most important

Blood Cells

• Eosinophils play a role in parasitic infections and allergic reactions
• Basophils are involved in inflammatory responses, especially in allergic reactions
• Lymphocytes (B cells and T cells) are responsible for specific immune responses
• Monocytes mature into macrophages, which engulf foreign particles and debris
• Neutrophils are the most abundant WBC, engulfing and destroying foreign particles and bacteria
• Mast cells play a key role in allergic reactions and inflammatory responses

Red Blood Cell Formation

• Mechanism of red blood cell formation: hematopoiesis in bone marrow, triggered by erythropoietin
• Red blood cells (RBCs) contain hemoglobin, which carries oxygen, and have an average lifespan of 120 days

Regulation of Blood Cells

• Cytokines are signaling molecules that stimulate immune responses
• Leukemia is a cancer of white blood cells
• Erythropoietin stimulates RBC production, primarily released by the kidneys in response to low oxygen levels
• Thrombopoietin stimulates platelet production, primarily produced by the liver
• Hematopoiesis is the process of blood cell formation

Platelet Function

• Platelet plug formation occurs through platelet activation, adhesion, and aggregation
• Platelets play a crucial role in blood clotting and hemostasis

Respiratory System

• Primary function of the respiratory system: exchange of oxygen and carbon dioxide between the environment and the body
• Ventilation refers to the movement of air in and out of the lungs
• Actual site of gas exchange: alveoli within the lungs
• Sequence of air route in the respiratory tree: mouth/nose, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli
• Type I alveolar cells are involved in gas exchange, while Type II alveolar cells produce surfactant
• Surfactant reduces surface tension, allowing for easier expansion of the lungs

Lung Mechanics

• Diaphragm and external and internal intercostal muscles contract, causing air to move into the lungs
• Inspiration occurs when the diaphragm descends, increasing lung volume, and expiration occurs when the diaphragm ascends, decreasing lung volume
• Typical intrapleural pressure: -5 mmHg
• Tidal volume: 500 mL, vital capacity: 4600 mL, inspiratory reserve volume: 3000 mL, expiratory reserve volume: 1200 mL, residual volume: 1200 mL

Blood Flow and Pressure

• Blood flow rate and blood pressure in the lungs are lower compared to other tissues
• Causes of fibrotic lung: chronic inflammation and scarring, emphysema: damage to alveoli, leading to difficulty breathing

This quiz covers the basics of sensory modalities, cutaneous sense lab activities, and cardiovascular dynamics. Test your knowledge of how sensory information is detected and processed, and various lab activities related to pressure sensation, touch localization, and more.