Histology and Circulatory System PDF

**ANAPHY LEC REVIEWER** **Module 1: Histology: Introduction and Method of Study** Definition of **Histology** - Is the study of tissues. - **Human Histology** may be defined as the study of the microscopic structure of biological materials derived from humans. **Electron Microscope** -...

**ANAPHY LEC REVIEWER** **Module 1: Histology: Introduction and Method of Study** Definition of **Histology** - Is the study of tissues. - **Human Histology** may be defined as the study of the microscopic structure of biological materials derived from humans. **Electron Microscope** - Use Electron beam wavelength. **Light Microscope** - Use visible light as their radiation. ***Light Microscope*** https://lh7-us.googleusercontent.com/-lH1w6dJVPujFdNp7ufyqhN9fD3A\_Yx042FZ\_B75qlZrHlFV2XaXt95OhoESYbIcwVuJkwsuhrAIhsWNanrY52mKfKPO5\_l7PV7mjY5HKTL3J4pmMxHb1PPk8DPo-8IX3wZL0O5qxBwDEbRvae1vvA=s2048 ***Electron Microscope***  **Human Circulatory and Cardiovascular System** Features of Circulatory System: - Consist of blood, heart, blood vessels, and lymph. - Consists of four chambers: two ventricles and two auricles. - Blood vessels transport oxygenated blood and nutrients to all parts of the body. - Possesses a body-wide network of blood vessels: arteries, veins, and capillaries. Components of the Circulatory System - Heart - Muscular organ pumping blood in the body - Right and left atrium, right and left ventricle, - Atriums collect the blood in the heart - Ventricles pump it to different organs. Arteries - Carry blood away from the heart. - Carry oxygenated blood to different parts of the body. Veins - Carry deoxygenated and oxygenated blood from the lungs into the heart. Capillaries - Smallest blood vessels and present in the lungs and muscles. ***Difference between Arteries, Veins, and Capillary*** https://lh7-us.googleusercontent.com/IHOuRMN02-B3JsxbdRArD1O-wWAwBaQmVhk-t5ehNscsNtkN-hAjo1kNzMKyVuh1hk-rVbFQlws7EpqLBmQKWuNCHkwkRe8PBeaRFFHWbHs-1kVzNRDMARkjK221aLsGsPwPwT\_tXa8xBk-QOkKF2g=s2048 ***Types of Blood Circulation*** Systemic circuit - Blood travels out of the left ventricle, to the aorta, to every organ and tissues in the body, and then back to the right atrium. Pulmonary circuit - Moves blood between the heart, lungs, and back. Pulmonary arteries - Carry deoxygenated blood. Systematic arteries - Carry oxygenated blood. Pulmonary circuit pump - Right side of the heart. Systematic circuit pump - Left side of the heart. Pulmonary circuit's components - Found mainly in the abdominal cavity. Systemic circuit's components - Found in all over the body. **Components of Blood** - Main function is to transport nutrients and oxygen to the cells of the body. 1\. Red blood cells (RBC) - Transport oxygen around the body. 2\. White blood cell (WBC) - Fight infection. 3\. Platelets - These clot prevent blood loss during injury. 4\. Plasma - Liquid part of the blood. Heart Beat - Triggered by electrical impulses that travel down a special pathway through your heart. SA node ( sinoatrial node) - Heart's natural peace maker AV node (atrioventricular node) - Cluster of cells in the center of the heart between the atria and ventricles. His-Purkinje Network - This pathway of fibers sends the impulse to the muscular walls of the ventricles and causes them to contract.  Blood Pressure - Measure of the force that your heart uses to pump blood around your body. - Systolic pressure -- the pressure when your heart pushes blood out. - Diastolic pressure -- the pressure when your heart rests between beats. Diseases of the Cardiovascular System 1\. Hypertension - Also called high blood pressure where the blood pressure is abnormally high. 2\. Atherosclerosis - Narrowing of arteries due to the plaque buildup on the artery walls. 3\. Stroke - Happens when the blood supply to part of the brain is cut off. **Digestive System** Components of the Digestive System - The function of this system is digestion and absorption. - Digestion is the breakdown of food into small molecules, which are then absorbed into the body. 1\. Mouth - It begins the digestive tract and digestion starts here. food taken are chewed here in order for them to be swallowed easily. 2\. Esophagus - Has muscles which allows it to perform muscular contractions known as peristalsis. 3\. Stomach - Pear-shaped enlargement of the alimentary canal. It secretes digestive juice known as gastric juice. 4\. Pancreas - It is a gland found behind the stomach. It secretes digestive enzymes into the duodenum. 5\. Liver - It produces bile which are secreted into the small intestine. 6\. Duodenum - It is the first part of the small intestine. It continuous the digestion of the food. 7\. Small intestine - Located between the stomach and the large intestine. 8\. Large intestine - Last part of the digestive system. Made up of rectum, colon, and caecum. 9\. Rectum - Connects the colon to the anus. 10\. Anus - The opening at the end of the alimentary canal. **Diseases arising from consuming poor diet:** Obesity - Complex diseases involving an excessive amount of body fat. Type 2 diabetes - Impairment in the way the body regulates and uses sugar as a fuel. - Chronic condition that results in too much sugar circulating the bloodstream. **Structure and Function of the Lymphatic System** - Is a network of tissues, vessels and organs that works together to move a colorless, watery fluid called lymph. Lymph or lymphatic capillaries - Are tiny thin-walled vessels, closed at one end and located in the spaces between cells throughout the body. Lymphatic veins - Slightly larger in diameter and have greater osmotic pressure than blood capillaries. Lymphatic vessels - Thin-walled vessels structured like blood vessels that carry lymph. Primary Lymphoid Organs - Also called central lymphoid organs - It is where immature lymphocytes develop. - Includes thymus and bone marrow. Secondary Lymphoid Organs - It is where antigen is localized so that it can be effectively exposed to mature lymphocytes - Includes like spleen, lymph nodes, tonsils, etc. Lymphatic nodules - Filter and attack antigens Thymus - Site of T-lymphocyte maturation and differentiation. Spleen - Filters blood and recycles aged erythrocytes and platelets. **Types of Immune Defenses** Physical and chemical barriers - Always ready and prepared to defend the body from infection. - Includes like skin, tears, mucus, etc. Inflammatory Response - Occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. Phagocytes - Act by migrating to infected areas and by ingesting and killing micro-organisms. Protective proteins - Antibody, also called immunoglobulin, a protective protein produced by the immune system in response to the presence of a foreign substance, called an antigen. Disorders of the Immune System Immunodeficiency - Also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Allergy - Immune system response to a foreign substance that's not typically harmful to your body. Autoimmune disease - Is a condition in which your immune system mistakenly attacks your body. **Anatomy of the Brain** Frontal lobe - Suppresses socially inappropriate behavior. Plays a role in the choice between good and bad actions. Temporal Lobe - Assists with the perception and interpretation of sound. Brainstem - Allows the transfer of information between the brain and body. Parietal lobe - Assists with the interpretation of touch. Plays a role in the knowledge of numbers and their relationship. Occipital lobe - Processes and makes sense of visual information. Cerebellum - Plays a major role in balance and voluntary motor skills. **Anatomy of the Eye** Sclerotic Layer - A tough, white-coloured protective layer that surrounds the eye and helps maintain its shape. Conjunctiva - A clear, thin layer covering the front of the eyes. Aqueous humour - A watery liquid that fills the space between the cornea and the lens. Ciliary muscles - Change the shape of the lens to bring images into focus Suspensory ligaments - Holds the lens in place. Blind spot - Where blood vessels and the optic nerve join the eyeball. Yellow spot - A section of the retina directly behind the pupil that contains a large number of colour-sensitive cells. Choroid - A black layer that forms part of the inside lining of the eye behind the lens. Vitreous humour - A jelly that helps maintain the shape of the eye. Cornea - This is the front layer of your eye. Its dome-shaped and it works by bending the light that enters your eye. Pupil - The black dot in the center of your eye that acts as a gateway for light. Iris - Typically referred to as your eye color. A muscle that controls the size of your pupil. Lens - Behind the iris and pupil. It works with your cornea to focus the light that enters the eye, much like a camera. Retina - Located at the back of the eye, a layer of tissue that transform the light coming into your eye into a electrical signals. Optic nerve - This part of your vision works as the connecting element between the retina and the brain. Tears - Most commonly thought of in relation to crying, tears are meant to keep your eyes wet and help you focus clearly. **Sensory Organs** Sensory receptor - Structure that reacts to a physical stimulus in the environment whether internal or external. - A sensory nerve ending that receives information. **4 types of receptors** Internal receptors - Also known as intracellular or cytoplasmic receptors. - Found in the cytoplasm of the cell. Cell-surface receptors - Also known as transmembrane receptors - Spans the plasma membrane and perform signal transduction. Ion channel-linked receptors - Bind a ligand and open a channel through the membrane that allows specific ions to pass through. G-protein-linked receptors - Bind a ligand and activate a membrane protein called a G-protein. Transduction - Refers to synaptic events wherein an electrical signal, known as an action potential, is converted into a chemical one via the release of neurotransmitters. Perception - Is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. 5 categories of sensory receptors 1\. Mechanoreceptors - Responds to mechanical pressure or distortion. 2\. Thermoreceptors - Specialized neurons designed to be sensitive to changes in temperature. 3\. Proprioceptors - Sensory receptor which receives stimuli from within the body, especially one that responds to position and movement. 4\. Pain receptors - Also called nociceptors, a group of sensory neurons with specialized nerve endings widely distributed in the skin, deep tissues. 5\. Chemoreceptors \- stimulated by a change in the chemical composition of their immediate environment. Rod cells - Responsible for detecting light/dark. Sensitive to low light intensities, so are made the best use of at night. Cone cells - Has a different pigment called iodopsin. Has three types of pigments: red, green, and blue cones. **Sense of Hearing** Human ear - Organ of hearinf and equilibrium that detects and analyzes sound by transduction. Pinna - Picks up sound waves from the air and guides them into the auditory canal External Auditory canal - Transmit sound waves from the pinna to the eardrum Eardrum - Transmit sound waves from the auditory canal to the ossicles. Ear ossicles - Transmit sound waves from the lympanic membrane to the oval window Eustachian tube - A tube that connects the middle ear with the pharynx. Oval window - Transmits sound waves from stirrup to the inner ear. Round window - Absorbs excess sound waves Cochlea - Contains the organ of corti which converts sound waves into nerve impulses Utriculus and sacculus - Able to detect changes in the position of the head with respect to gravity and are therefore involved in balance. Semi-circular canals - Able to detect the direction and rate of movement of the head and are therefore involved in balance. Perilymph - The liquid that surround the membranous labyrinth in the inner ear. Endolymph - The liquid that is found inside the membranous labyrinth of the inner ear. Auditory nerve - The nerve that carries nerve impulses from the ear to the brain. Diseases Affecting the Sense Organs 1\. Myopia (nearsightedness) - Common vision defect - Light rays of images focus in front of the retina rather than directly on the retina 2\. Hyperopia (farsightedness) - Common vision condition in which you can see distant objects cleary, but objects nearby may be blurry. 3\. Astigmatism - A defect in the eye caused by a deviation from spherical curvature, which resulted in distorted images. 4\. Hearing loss - Unable to partially or completely hear sound in one or both of your ears. 5\. Vertigo - Most common type, is often cause by a problem with the balance mechanisms of the inner ear.