Download Basic Medical Sciences

Basic Medical Sciences
Module Co-ordinator : Dr Aoife Gowran- [email protected]
MSc Bioengineering
MSc Physical Sciences in Medicine
JS Biomedical Engineering
MSc Health Informatics
MSc Medical Device Design
Module Learning Objectives
•  Describe the basic functions of the human body
•  Define anatomy and physiology of the human
body
•  Be familiar with medical terminology
•  Appreciate the mechanisms of disease
(e.g., diabetes, ageing etc.)
•  Give examples of disease symptoms, diagnosis
criteria and medical intervention
•  Integration into your own discipline
Learning Methods
Lectures
Specialist lectures
Lab visits*
Student seminars
Timetable
Every Friday 2-6pm, Michaelmas term
Full TT in your module descriptor
Lecture notes
Blackboard
http://mymodule.tcd.ie/
Department of Physiology website
https://medicine.tcd.ie/physiology/student/
Also in my GET folder gowrana
For instructions on how to gain access to GET folders
see:
http://www.tcd.ie/iss/internet/getput_access.php
Learning tools: Books
Human Physiology
by Lauralee Sherwood 2010 Brooks & Cole,
Hamilton, Lending S-LEN 612 M98*6;4-18, John Stearne, Lending SJ 612 M98*6;1-6
Fundamentals of anatomy & physiology
by Martini, Nath & Bartholomew,
John Stearne, Lending SJ 611 M91*8
Wheater's functional histology: a text & colour atlas
by Burkitt, Young & Heath,
Hamilton, Lending S-LEN 599 +L93*4;1-16
Essential cell biology
by Bruce Alberts et al.,
Hamilton, Lending S-LEN 574.87 N82*2;1-14
Gray's anatomy for students
by Drake et al.,
Hamilton, Lending S-LEN 611 P5*1;6, John Stearne, Lending SJ 611 P5*1
Learning tools: Websites
http://www.nlm.nih.gov/medlineplus/
http://www.ncbi.nlm.nih.gov/pubmed/
http://www.nature.com/nature/index.html
http://www.ted.com
http://www.thenakedscientists.com/HTML/articles/medicine/
http://medgadget.com
Assessment - 2 Parts
****NB FOR MSc STUDENTS ONLY! NB***
1. Student seminars (50%)
•  Topic is negotiated
•  15 Minute Talk and 5 mins Q&A session (total 20 mins)
•  Provide the following in hard copy on the day:
1. Print out of slides (1 copy)
Seminar I 2nd November
Seminar II 7th December
Assessment
****NB FOR MSc STUDENTS ONLY! NB***
2. Seminar paper (50%)
21st January 2013
•  Topic is chosen from the BMS student seminars (NOT
YOUR OWN)
•  MAX 4,000 words
•  Provided in hard copy only (Physiology Dept. Office)
•  Integration of relevant BMS information (20%)
•  Coherency for a non-expert audience (10%)
HAND IN by 21st January 2013
Assessment
****NB FOR JS Biomedical Engineering STUDENTS ONLY! NB***
Written exam in Trinity term, 2h
2 sections:
1.  written section consisting of short-answer questions (60%)
2.  multiple-choice/fill in the blanks section (40%)
Questions before we start?
Levels of Organization
4. Organ
3. Tissue
2. Cellular
Structural & Functional specialization
1. Fundamental chemical
TISSUES OF THE BODY
A group of cells functioning together is a TISSUE
Interstitial fluid
vs
plasma
extracellular fluid
Tissue types
function dependent on structure
structure dependent on protein composition
1. NEURAL - neurones
3. MUSCLE - myocytes
Blood
Ciliated
Simple
Stratified
Bone
squamous
cuboidal
columnar
2. EPITHELIUM - epithelial
Cartilage
4. Connective tissues
Nervous tissue
–  Consists of cells specialized for initiating and
transmitting electrical impulses
–  Found in brain, spinal cord, and nerves
Epithelial tissue
–  Consists of cells specialized for exchanging
materials between the cell and its environment
–  Organized into two general types of structures
•  Epithelial sheets
•  Secretory glands
Muscle tissue
–  Specialized for contracting which generate tension and
produce movement
•  Stirated (skeletal & cardiac)
•  Smooth muscle (stomach, blood vessels)
Connective tissue
–  Connects, supports, and anchors various body parts
–  Distinguished by having relatively few cells dispersed
within an abundance of extracellular material
–  Examples: Blood, Bone, Cartilage
Organs
A group of different tissues joined
together acting in unison in order
to exert a common function(s)
Organs co-operate together
Take for example the stomach……
Example: Stomach (all 4 10 tissue types)
- Inside of stomach lined with epithelial tissue
- Wall of stomach contains smooth muscle
- Nervous tissue in stomach controls muscle
contraction and gland secretion
- Connective tissue binds all the above tissues
together
Integration of organ function
Ch. 1 Sherwood
6. Organism Level
5. Systems
Body Systems
•  Groups of organs that perform related functions
•  Interact to accomplish a common activity
•  Essential to survival of the whole body
•  Do not act in isolation from one another
•  Human body has 11 systems
Body Systems
•  Circulatory System
•  Immune System
•  Digestive System
•  Nervous System
•  Respiratory System
•  Endocrine System
•  Urinary System
•  Integumentary System
•  Skeletal System
•  Reproductive System
•  Muscular System
? Adaptive significance of functional organ systems
Homeostasis
Amoeba
Multi cellular organism
Homeostasis
•  Defined as maintenance of a relatively stable
internal environment
–  Does not mean that composition, temperature, and
other characteristics are absolutely unchanging
•  Homeostasis is essential for survival and
function of all cells
•  Each cell contributes to maintenance of a
relatively stable internal environment
Homeostasis
Factors homeostatically regulated include
•  Concentration of nutrient molecules
•  Concentration of O2 and CO2
•  Concentration of waste products
•  pH
•  Concentration of water, salt & other electrolytes
•  Volume and pressure
•  Temperature
Role of Body Systems in Homeostasis
Role of Body Systems in Homeostasis
Homeostatic Control Systems
•  Control systems are grouped into two classes
–  Intrinsic controls
•  Local controls that are inherent in an organ
–  Extrinsic controls
•  Regulatory mechanisms initiated outside an organ
•  Accomplished by nervous and endocrine systems
Maintenance relies on:
•  Detection of deviation
•  Integration of this info
•  Re-adjustments to restore balance
Disruptions in Homeostasis
•  Can lead to illness and death
•  Pathophysiology
–  Failure to detect deviations from the norm
–  Failure to integrate this info into a reaction
–  Failure to make required adjustments
An introduction to cellular physiology
Cells are living building blocks of all multicellular organisms
Chapter 2-Cellular Physiology
‘Human Physiology’, Sherwood
Principles of the Cell Theory
THE CELL IS THE BASIC UNIT OF LIFE
•  All new cells and new life arise only from preexisting cells
•  Cells of all organisms are fundamentally similar
in structure and function
•  An organism’s structure and function depends
on individual and collective structural
characteristics and functional capabilities of its
cells
Basic Cell Functions
•  Control exchange of materials between cell &
surrounding environment
•  Sensing and responding to changes in surrounding
environment
•  Reproduction
–  Exception, Nerve cells and muscle cells lose their ability to
reproduce during their early development
Basic functions of cell cont’d
•  chemical production of energy (ATP)
•  obtains O2/nutrients from surrounding environment
•  eliminates waste materials from cell
•  manufacture new proteins
Bone
Progeniter cells
DIFFERENTIATION
Muscle
Specialist functions of cell
Sperm
•  Bone cells deposit calcified matrix
•  Muscle cells contract
5µm
Neuronal
•  Sperm cells travel great distances
•  Neuronal cells transmit electrochemical signals
400µm
•  All cells contain the same genes
•  Different cell types “switch on/off” different genes
•  Express (make) different proteins
•  Allows different cell types to have specific functions
- muscle cells contract
- bone cell deposit extracellular matrix
- cells lining GI tract secrete digestive enzymes
‘Typical’ Eukaryotic Cell
Ultrastructure of mammalian cell
Nucleus
•  Largest single organized cell
component
•  Enclosed by a double-layered
nuclear envelope
•  Stores genetic material (genes) in the form of DNA
•  Acts as a central control-point of cell function
•  Dictates which proteins should be made by cell
DNA - deoxyribonucleic acid
Watson,
Crick,
Franklin
Nucleic acid bases
A -adenosine
T -tyrosine (uracil in mRNA)
G -guanine
C -cytosine
DNA packaging
Chromosomes: Long DNA linear molecule associated with
proteins that pack & fold it into more compact form
•  46 in human (23 pairs)
•  Carry genes in association with
proteins
•  Each gene codes for a protein
•  20,000-25, 000 genes
Making new proteins
Flow of genetic material
DNA
transcription
RNA
New Protein
SPECIFIC FUNCTION
translation
Happens within the
cell
involves action of
several Enzymes
RNAs
Proteins
The genetic code
Active proteins
Protein folding
Post translational modification
1
Primary
aa seq
3 Tertiary
folded peptide
2
Secondary
αβ helices
4 Quaternary
folded POLYpeptides
Cytoplasm
Includes all material inside
the cell except the nucleus
3 Components
1.  Cytosol - intracellular fluid; semi gelatinous, contains
nutrients and proteins, ions and waste products.
2. Inclusions - particles of insoluble material; direct contact with
cytosol e.g.,protein fibers, ribosomes and proteasomes.
3. Organelles - membrane bound compartments; play specific
roles in the function of the cell e.g., production of energy
Several ORGANELLES are contained
within the cytoplasm
Membranous: Mitochondria
Endoplasmic reticulum
Golgi complex
Lysosomes
Peroxisomes
Non-membranous: ribosomes, cytoskeleton
Mitochondria
Small spherical; double membrane
Outer & inner membrane
Folded into leaflets - cristae
Central lumen – mt Matrix
Inter membrane space
•  Energy organelle
–  Major site of ATP (adenosine triphosphate) production
–  Contains enzymes for citric acid cycle and electron transport chain
ATP is used by the cell for cellular processes:
- Movement/Mechanical work
-  Transport of molecules against a concentration gradient
-  Biochemical reactions
-  Synthesis of new chemical compounds
Endoplasmic reticulum
Endoplasmic Reticulum (ER)
•  Elaborate fluid-filled membranous system
distributed throughout the cytosol
•  Primary function
–  Protein and lipid manufacture
•  Two types
–  Rough ER (protein synthesis)
•  Projects outward from smooth ER as stacks of
relatively flattened sacs
•  Surface has attached ribosomes
–  Smooth ER (lipid synthesis)
•  Mesh of tiny interconnected tubules
Golgi complex
Golgi Complex
•  Closely associated with ER
•  Consists of a stack of flattened, slightly curved,
membrane-enclosed sacs called cisternae
•  Number of Golgi complexes per cell varies with
the cell type
•  Functions “Protein post production”
–  Processes raw materials (RER) into finished products
–  Sorts and directs finished products to their final
destinations
–  Packages secretory vesicles to release by exocytosis
Lysosomes & Peroxisomes
Lysosomes
Cytoplasmic vesicle, high pH
Contain digestive enzymes
Function
Digestive system of the cell
They breakdown old worn out organelles,
bacteria, abnormal proteins
Products of digestion can be reused
Cytoskeleton
Microtubules
Micro filaments
Intermediate filaments
Functions
Cell shape
Internal organization
Intracellular transport
Assembly of cells into tissues
Movement
Element
Function
•  Transport secretory vesicles
•  Movement of specialized cell
projections
•  Form mitotic spindle during cell
division
•  Contain Tubulin protein
Microfilaments •  Contractile systems
•  Mechanical stiffeners
•  Contain 2 chains of Actin protein
Intermediate •  Help resist mechanical stress
•  Contain Keratin
filaments
Microtubules
Plasma Membrane
Plasma Membrane Structure
•  Fluid lipid bilayer embedded with proteins
–  Most abundant lipids are phospholipids
•  Polar end of phospholipid is hydrophilic
•  Nonpolar end of phospholipid is hydrophobic
•  Also has small amount of carbohydrates
–  On outer surface only
•  Cholesterol
–  Tucked between phospholipid molecules
–  Contributes to fluidity and stability of cell
membrane
Plasma Membrane
•  Extremely thin layer of lipids and protein that forms
outer boundary of every cell
•  Controls movement of molecules between the cell
and its environment
•  Participates in joining cells to form tissues and
organs
•  Plays important role in the ability of a cell to
respond to changes in the cell’s environment
Cell-To-Cell Adhesions
•  Adhesions bind groups of cells into tissues and package
them into organs
•  Once arranged, cells are held together by three different
means
Cell adhesion molecules (CAMs)
- Plasma membranes temporary adhesion
Extracellular matrix
- Major types of protein fibers interwoven in matrix
Specialised cell junctions
- more permanent adhesion
EXTRACELLULAR MATRIX (ECM)
•  Secreted by cells - biological “glue”
•  Meshwork of fibrous proteins in
a watery gel-like substance composed
of carbohydrate
1.
COLLAGEN
tensile strength
2.
ELASTIN
allows stretch and recoil
3.
FIBRONECTIN
cell adhesion
holds cell in position
Bone
- hard extracellular matrix
Skin
-flexible
Lung
- elastic
Specialized Cell Junctions
•  Three types of specialized cell junctions
– Desmosomes
– Tight junctions (impermeable junctions)
– Gap junctions (communicating junctions)
Desmosomes
•  Act like “spot rivets” that
anchor two closely adjacent
nontouching cells
•  Most abundant in tissues
that are subject to
considerable stretching
Tight junctions
•  Firmly bond adjacent cells
together
•  Seal off the passageway
between cells
•  Found primarily in sheets
of epithelial tissue
•  Prevent undesirable leaks
within epithelial sheets
Gap junctions
•  Small connecting tunnels
formed by connexons
•  Especially abundant in
cardiac and smooth muscle
•  In other tissues: permit
unrestricted passage of
small nutrient molecules
between cells
•  Also serve as method for
direct transfer of small
signaling molecules from
one cell to the next
Blisters
Stress shears the proteins connecting the different
layers in the skin separate
Cell Fates
Apoptosis
Cell
Renewal
Cell death
Necrosis
Tissue homeostasis
(remodelling)
Blastocyst
(totipotent)
Stem cells
Neural stem cells
Learning outcomes
•  Define: homeostasis, differentiation using egs
•  Describe the form and function of the 4 tissues
•  Recall the intracellular structures
•  Know the function of each
•  Understand how cells are held together
•  Show an appreciation of pathology of intracellular
structures.
•  Be aware of the different cell fate options