Lecture 2: Introductory Physiology: Systems, Organs, Cells and Genes PDF

1 Introductory Physiology Lectures 1 – 8 Foundations for understanding Systems & Integrated Physiology 1 Overview and Scientific Process Think! How the body 2-3 Systems, tissues, cells (genes)...

1 Introductory Physiology Lectures 1 – 8 Foundations for understanding Systems & Integrated Physiology 1 Overview and Scientific Process Think! How the body 2-3 Systems, tissues, cells (genes), body water is organised Basis for 4-7 Transport processes (across cell membranes) Understanding Bio-electric potentials (and ion distribution) System Function Just 1 of 11 8 Nerve Physiology systems 2 Lecture 2: Integrated Physiology: Systems, Organs, Cells and Genes Learning Objectives of this lecture Revision of Key points of Lecture 1 (from Tuesday) Distinguish between the 11 body systems, describe their major organ and function Gain an appreciation of integration and scale Distinguish between the four tissue types and describe their functions Self-Directed Learning Read your text book - Fox 3 Systems 1. Skeletal 4 Systems 1. Skeletal Humans have 206 bones Both male and female have 24 ribs (12 sets, front and back) shown by experiment: Flemish anatomist Vesalius in 1543 5 Systems 1. Skeletal Two jobs support weight of body withstand forces of contracting muscles Mature bones contain three cell types 6 Systems 1. Skeletal 7 Systems 1. Skeletal 8 Systems 1. Skeletal 9 Systems 1. Skeletal Three cell types Osteoblasts make bones for lifetime of organism (deposition) 10 Systems 1. Skeletal Three cell types Osteoblasts make bones for lifetime of organism (deposition) Osteocytes - terminally differentiated osteoblasts surrounded by calcified matrix made from hydroxyapatite (Ca2+ mineral) and osteoid (protein) 11 Systems 1. Skeletal Three cell types Osteoblasts make bones for lifetime of organism (deposition) Osteocytes - terminally differentiated osteoblasts surrounded by calcified matrix made from hydroxyapatite (Ca2+ mineral) and osteoid (protein) Osteoclasts secrete acid to breakdown hydroxyapatite and enzymes to breakdown osteoid (resorption) Ability to make and break-down bone allows broken limbs to be repaired Bones get weaker >30 yrs, as rate of resorption > deposition 12 Systems 1. Skeletal Three cell types Osteoblasts make bones for lifetime of organism (deposition) Osteocytes - terminally differentiated osteoblasts surrounded by calcified matrix made from hydroxyapatite (Ca2+ mineral) and osteoid (protein) Osteoclasts secrete acid to breakdown hydroxyapatite and enzymes to breakdown osteoid (resorption) Ability to make and break-down bone allows broken limbs to be repaired Bones get weaker >30 yrs, as rate of resorption > deposition 13 An understanding of Physiology helps us understand how drugs work… … an example 14 Systems 1. Skeletal Long bones grow during childhood: a fourth cell type chondrocytes, divide and enlarge in response to growth hormone (GH) Lack of GH = achondroplasia (dwarfism) Chondrocytes become trapped during calcification, die, and are replaced by osteoblasts GH treatment works for children, but won’t work in adults Bones stop elongating in late adolescence once the epiphyseal plate forms plate 15 Systems 1. Skeletal Bone Marrow contains stem cells which make red blood cells and cells of immune system Example of overlap between systems 16 Systems 2. Muscular 17 Systems 2. Muscular 18 Systems 2. Muscular 19 Systems 2. Muscular 20 Systems 2. Muscular Three types of muscle: 1. Skeletal Muscles move the skeleton (with three exceptions – see later) 21 Systems 2. Muscular Three types of muscle: 1. Skeletal Muscles move the skeleton (with three exceptions – see later) 2. Cardiac Muscle allows contraction of the heart 22 Systems 2. Muscular Three types of muscle: 1. Skeletal Muscles move the skeleton (with three exceptions) 2. Cardiac Muscle allows contraction of the heart 3. Smooth muscle allows contraction and relaxation of the vasculature (blood vessels) and digestive system i.e. overlap between systems 23 Systems 2. Muscular Muscles are controlled by “animal electricity”, Luigi Galvani (c. 1780): Experiment Fresh muscles from a dead frog suspended on a metal wire contracted during a thunderstorm See Lab classes and later lectures 24 Systems 3. Nervous Nerve cells connect all parts of the body to the brain The brain is made of 1011 nerve cells (0.1% of total cells in the body) Nerve cells make 1014 connections (synapses) with other nerve cells in the brain Nerves conduct electrical impulses and control muscle movement, hormone secretion Nerve function can be blocked by neurotoxins with both therapeutic purposes, or fatal consequences See Labs and later lectures 25 Systems 4. Digestive Gastrointestinal tract (GIT) is a 4.5 metre hollow tube stretching from your mouth to your rectum Water and food enter the GIT Useful material is absorbed Waste gas is excreted via lungs (see Respiratory system) Waste water is excreted via kidneys (see Renal System) Unabsorbed material is lost* as faeces * Not excretion as it never entered the body (What – next slide!) 26 Systems 4. Digestive GIT - mechanisms of absorbtion and secretion Skeletal muscle not connect to bone 1. Tongue 2. Anal sphincter Overlap between systems = integration 27 Systems 5. Urinary Water is absorbed into blood and kidneys regulate the total amount of water in the blood An excess of water is excreted via the kidneys What’s the definition of an excess – kidneys are major regulatory organs How does water leave the blood and become urine? 28 Systems 5. Urinary Kidneys - mechanisms of excretion 29 Systems 6. Respiratory O2 is essential for oxidative phosphorylation, the major pathway for ATP production in the body (see Biochemistry) 30 Systems 6. Respiratory Diaphragm contraction and relaxation moves lungs and drives gas exchange Skeletal muscle not connect to bone #3 - diaphragm Overlap between systems = integration 31 Systems 6. Respiratory Diaphragm contraction and relaxation moves lungs and drives gas exchange 32 Systems 6. Respiratory Diaphragm contraction and relaxation moves lungs and drives gas exchange 33 Systems 6. Respiratory ATP production occurs in virtually every cell in the body, so O2 must reach these cells Glucose is also required to reach these cells All cells also produce CO2 and other waste products, hence the need for a... 34 Systems 7. Circulatory Heart pumps blood around the body Beats 3,000,000,000 times O2 carried by erythrocytes (RBC) and nuritents dissolved in plasma transported to cells CO2 and waste transported for excretion Each beat moves ~ 70 ml of blood - that’s a lot of RBCs: Every cell in your body is ~300,000,000,000 supported by two red blood cell 35 Systems 7. Circulatory Deoxygenated blood enters heart and is pumped to lungs Oxygenated blood returns to heart and is then pumped out to the rest of the body... 72 times per minute 36 Systems 7. Circulatory Deoxygenated blood enters heart and is pumped to lungs Oxygenated blood returns to heart and is then pumped out to the rest of the body... 72 times per minute 37 Systems 7. Circulatory Deoxygenated blood enters heart and is pumped to lungs Oxygenated blood returns to heart and is then pumped out to the rest of the body... 72 times per minute 38 Systems 7. Circulatory Deoxygenated blood enters heart and is pumped to lungs Oxygenated blood returns to heart and is then pumped out to the rest of the body... 72 times per minute 39 Systems 7. Circulatory Deoxygenated blood enters heart and is pumped to lungs Oxygenated blood returns to heart and is then pumped out to the rest of the body... 72 times per minute 40 Systems 7. Circulatory Deoxygenated blood enters heart and is pumped to lungs Oxygenated blood returns to heart and is then pumped out to the rest of the body... 72 times per minute 41 Systems 7. Circulatory Deoxygenated blood enters heart and is pumped to lungs Oxygenated blood returns to heart and is then pumped out to the rest of the body... 72 times per minute 42 Systems 7. Circulatory Deoxygenated blood enters heart and is pumped to lungs Oxygenated blood returns to heart and is then pumped out to the rest of the body... 72 times per minute Integration of circulation & endocrine systems Hormones secreted into the blood can reach any part of the body very quickly (though not as fast as nerve impulses) 43 Systems 8. Endocrine e.g. Adrenaline rush Increases heart rate, constricts blood vessels, targets blood flow to muscles e.g. melatonin regulates biorhythms e.g. insulin regulates blood glucose Integration of circulation & endocrine systems Hormones secreted into the blood can reach any part of the body very quickly (though not as fast as nerve impulses) 44 Systems 9. Immune Discrimination between self and non-self Innate responses Adaptive immunity Inflammatory response 45 Systems 10. Integumentory The largest organ system of an animal Comprising skin, hair, (feathers, scales), nails, skin glands and their products (sweat and mucus) Distinguishes, separates, protects and informs organisms of its surroundings (e.g. temp / touch receptors) Part of innate immune system sweat is ~pH4 and prevents bacterial colonisation Colour is determined by the level of melanin 46 Systems 11. Reproductive How egg and sperm give rise to offspring Interface of Physiology and Genetics 47 Major Organs of Body Systems System Major Organ Primary Function Muscular Skeletal Muscles Movement of skeleton Nervous Brain, CNS, PNS Regulation of other body systems Circulatory Heart Movement of Blood Respiratory Lungs Gas Exchange Urinary Kidney Blood volume Immune Bone marrow Defense Integumentory Skin Thermoregulation Skeletal Bones Movement Endocrine Hormone glands Hormone regulation Digestive Stomach/IntestineBreakdown of food Reproductive Gonads Eggs/Sperm 48 Lecture 2: Integrated Physiology: Systems, Organs, Cells and Genes Learning Objectives of this lecture Distinguish between the 11 body systems, describe their major organ and function Appreciate integration and scale Distinguish between the four tissue types and describe their functions Self-Directed Learning Read your text book - Fox  Integration & Scale 49 Whole Body (1) 1.7 m Systems (11) 105 Tissues (4) 17 µm Cells (5 x 1013) Genes (30,000) 50 The Proportions of The Human Figure - Vitruvian Man, 1490 Leonardo da Vinci 1.7 m 105 17 µm Typical Human Cell A “typical” human cell is ~100,000 times smaller than the human body 51 Scale: Genes & Proteins Chromosomes in the nucleus 3x109 bp DNA encode 30,000 genes DNA transcribed into RNA RNA translated into protein Proteins determine function of cell 52 Rhodopsin (348 aa) sensitive to light located in the retina ~4 cm ~4 nm Organ 107-fold larger than protein 53 CFTR (1480 aa) Cl- ion transporter ~2 m in all sectretory cells ~20 nm Organism 108-fold larger than protein 54 Lecture 2: Integrated Physiology: Systems, Organs, Cells and Genes Learning Objectives of this lecture Distinguish between the 11 body systems, describe their major organ and function Appreciate integration and scale Distinguish between the four tissue types and describe their functions Self-Directed Learning Read your text book - Fox 55 Tissue: specialised groups of cells with a common structure and function Four different types: Muscle Excitable tissue Nervous Connective Non-excitable tissue M N C E Epithelial 56 I – Muscle Tissue (3 cell types) Function Allows Movement Location Attached to bones* (skeletal) Walls of internal organs (smooth) Heart (cardiac) Distinguishing Characteristics Contractile 57 Skeletal Muscle Skeletal muscle fibres are long, thin and striated Attached to bones and tendons* (contraction -> moves skeleton) *except: tongue, anal sphincter, diaphragm Fibres arranged in bundles Groups of fibres within a whole muscle “recruited” by nerves to contract to give graded movement of the muscle 58 Cardiac Muscle Striated Heart ONLY Cells interconnected - continuous fabric Intercallated discs - couple cells electrically & mechanically All fibres in whole heart contract simultaneously 59 Smooth Muscle Not striated Digestive, urinary, & reproductive tract, blood vessels, bronchioles, Contractile tubing Circularly arranged - constricts lumen Rhythmic contraction - peristalsis 60 II - Nerve Tissue (two cell types) neurons neuroglia Function M N C E Transmits impulses for co-ordination, regulation, sensory perception Location Brain, Spinal Cord & Nerves Distinguishing Characteristics Connect to each other & other parts of body 61 Neurons Neurons Generate & conduct electrical events Dendrites (multiple) Receive inputs from other cells Cell Body Contains nucleus Axon (single) Conducts implusle to another neuron or effector (e.g. muscle) Unidirectional flow of information Longest axon in humans is ~1 metre long A single cell - where does it start and finish? 62 Neuroglia Structural & functional support to neurons (ave. 5 per neuron) Do not conduct electrical signals Neuroglia can divide Oligodendrocytes in CNS and Schwann cells in PNS 63 III - Connective tissue (lots of cell types) Function Binds, supports, protects, fills spaces, stores fat, makes blood cells Location Wide distribution throughout body M N C E Distinguishing Characteristics Has blood vessels Cells spaced apart with matrix (extracellular proteins and fluid) inbetween Located between and connected to other tissues 64 Connective tissue Dermis - collagen (protein) matrix supporting many different cell types (blood vessels, nerve cells - see next slide) Applied Physiology: How deep does a cut have to be before you bleed? 65 Connective tissue - e.g. adipose tissue Adipocytes - cells wrapped around fat globules Size of globule regulated by enzymes in cytoplasm of adipoctye 66 Connective tissue - e.g. bone Osteoblasts secrete calcite and become trapped by it forming osteocytes Osteocytes remain alive by receiving nutrients from blood vessels passing through central bone canal and branching through canaliculi (little canals) 67 Tissues form organs Organ: a structure within the body comprising two or more different tissue types e.g. skin 68 IV – Epithelial Tissue The body as you never seen it before… … next week 69 Lecture 2: Integrated Physiology: Systems, Organs, Cells and Genes Learning Objectives Systems, organs and function Integration, scale and tissue types Attend all lectures and labs Don’t just learn Physiology, make sure you understand it Philosophy of Science It’s not a fact, just a very good theory Self-Directed Learning Physiology is an integrated subject Read Me!