1. Cytology, Basic Genetics & Histology Flashcards
Anatomy
Study of structures that form the body
Physiology
How parts of the body works
Pathology
Study of abnormalities from normal function
Characteristics of life
- Metabolism
- Responsiveness
- Movement
- Reproduction
- Growth
- Differentiation
- Vital force / life force / Qi
Define the characteristics of life
- Metabolism: sum of all chemical processes in the body
- Responsiveness: ability to respond to changes in the environment
- Movement: movement in the whole organism or of individual organs, cells and structures inside cells.
- Reproduction: formation of new cells/production of a new individual
- Growth: increase in size or numbers
- Differentiation: development to a specialised state
- Vital force / life force / Qi: energy that flows throughout
Characteristics of death
- Loss of heartbeat
- Absence of breathing
- Loss of brain function
- No vital force / life force / Qi
Homeostasis
The condition of equilibrium/balance in the body’s internal environment maintained by the body’s own regulatory processes.
It’s dynamic and ever changing, whilst always remaining within certain limits to ensure optimal functioning.
What are the variables that must be kept within narrow parameters for homeostasis?
- Core temperature (36.5 - 37.5°C)
- Water & electrolyte concentrations
- pH of bodily fluids
- Blood glucose levels
- Blood & tissues o2/co2 levels
- blood pressure
- flow of life force
Name the homeostatic control systems
- Disruptors
- Detectors
- Control centre
- Effector
Explain the homeostatic control systems
- Disruptors: Change homeostatic parameters
- Detectors: Receptors that detect disruption (often nerves)
- Control centre: Determines limits within which parameters should be maintained - evaluates input, generates output
- Effector: Structures that receive output
Name the 2 feedback systems
Positive & negative
Negative feedback
The output reverses the input
The effector response decreases the effect of the original stimulus
Positive feedback
Strengthens change in one of the body’s controlled conditions
Negative feedback examples
Increasing or decreases…
- Body temperature
- Blood glucose
- Blood pressure
Positive feedback examples
- Childbirth
- Milk production
- Enzyme reactions
- Immunity
- Blood clotting
Body fluids are either…
- Intracellular (inside cell)
- Extracellular (outside cell)
Interstitial fluid
Fluid that surrounds the cells and bathes them
Plasma/intravascular fluid
Fluid within the blood
Name the body organisation
- Atoms & molecules
- Cells
- Tissues
- Organs
- Systems
- The organism
- Vital force / life force / Qi
Explain each body organisation
- Atoms & molecules: Chemical level
- Cells: The smallest living unit in the body
- Tissues: Groups of cells that work together to perform a function
- Organs: Groups of tissues working together
- Systems: Related organs that have a common function
- The organism: All body parts together
- Vital force / life force / Qi: The energy that creates life
What are the systems of the human body?
- Skeletal
- Muscular
- Respiratory
- Cardiovascular
- Digestive
- Endocrine
- Lymphatic
- Integumentary
- Urinary
- Reproductive
- Nervous
- Immune
Body cavities
- Cranial
- Thoracic
- Abdominal
- Pelvic
In terms of body cavities, what does the presence of the diaphragm do?
It’s presence differentiates the thoracic cavity (above it) from the abdominal cavity (below it)
The cell theory
- All known living things are made up of cells & vital force
- The cell is the structural & functional unit of all living things
- All cells come from pre-existing cells from division
- Cells contain hereditary information in the form of DNA (passed from cell to cell)
- All energy flow of life (metabolism & life force) occurs within cells
Cell memory
Cell memory describes the ability of cells to remember experiences which influence vital force in our cells & body
Traumatic experiences & even negative beliefs may be stored as a negative charge of energy in cells
Vital force is free flowing through the body in a healthy person but can become blocked creating the possibility for disease.
Disease
A disruption of body physiology can cause disease
Cells are interconnected, when this is disrupted, diseases manifest in these organs
Oxidative damage
Occurs due to toxins, stress, smoking, diets rich in refined sugar & processed foods
Oxidative damage influences key cell structures & even causes genetic mutations - this occurs during the development of cancer
Free radicals
They cause oxidative damage
Unstable & highly reactive molecules, looking for a spare electron and will rob other to get it
Missing electrons can be donated by an antioxidant
Antioxidants
Neutralises free radicals
- Vitamin C
- Vitamin E
- Beta-Carotene
- Vitamin A
Prokaryotic cells
No nucleus & no membrane bound organelles
Far smaller (very few structures)
Has a cell wall
Prokaryotic cells include: bacteria
Cell division through binary fission (rapid mitosis)
Eukaryotic cells
Contains a nucleus & membrane bound organelles
Bigger
No cell wall in humans, online in plants & fungi
Eukaryotic cells include:human/animal, plants & fungi
Cell division through mitosis
Cell wall function
Provides strength & rigidity to cells and surround the cell membrane
Cytosol
Basic watery fluid inside a cell
What are organelles
Small specialised structures within the cell, e.g. ribosomes produce proteins
Cytoplasm
Cell content excluding the nucleus (includes the cytosol & organelles)
Cell membrane
Flexible, semi-permeable membrane that separates the cells external and internal environment
Structurally it is a phospholipid bilayer
The membrane is embedded with transmembrane proteins & other fats e.g. cholesterol
The membrane controls substance movement in and out of cells
phospholipid bilayer
The ‘hydrophobic’ lipid tails face inwards whilst the ‘hydrophobic’ phosphate heads face outwards
Hydrophobic
Water hating
Hydrophilic
Water loving
Transmembrane protein functions
- Transport of substances in & out of cells: this includes the movement of charged particles, e.g. Hydrogen and larger molecules like glucose
- Immunological identity: helps our immune cells recognise our own cells (stops our WBC from attacking our body cells)
- Receptors: recognition sites for hormones etc.
What are the types of cell junctions
- Tight junctions: found in the stomach, intestines and bladder. They fuse together (transmembrane proteins) to reinforce the junctions & seal off passageways (prevents leaking)
- Gap junctions - small fluid filled tunnels between neighbouring cells e.g. nerves
The key organelles found in body cells
- Nucleus (& nucleolus)
- Mitochondria
- Ribosomes
- Endoplasmic reticulum ER
- Golgi apparatus
- Lysosomes
- Cytoskeleton
Nucleus
The nucleus is a spherical structure that contains the body’s genetic information in the form of DNA
The nucleus controls all cell functions, hence is the ‘brain of the cell’. It contains a ‘nucleolus’ which produces RNA
Which body cells do not contain a nucleus & why?
RBC - These lose their nucleus during development to maximise the space available to carry oxygen
What surrounds the nucleus?
Surrounded by a doubled layered ‘nuclear membrane’ which separates the nucleus from the cytoplasm
The membrane is continuous with the rough endoplasmic reticulum ER
The nuclear membrane contains nuclear pores for substance movement in & out of the nucleus
Chromosomes
Thread like structures of nucleic acids & proteins found in the nucleus of most living cells, carrying genetic information in the form of genes
The hereditary units called ‘genes’ are arranged along chromosomes.
Chromosomes of formed of DNA that has coiled up
How many chromosomes does a normal somatic/diploid cell have?
46 chromosomes (or 23 pairs)
How many chromosomes does a sex gamete/haploid cell have?
23 chromosomes
Histones
Proteins which double helix DNA coils around
Chromatin
thread like fibres of DNA before condensing into chromosomes
XX Chromosomes
Female
XY Chromosomes
Male
Possible issues regarding XY Chromosomes
If there is a genetic disease on the single X chromosome, the Y cannot counteract it; this may lead to sex linked, genetic diseases in males.
Genes
Genes are sub-sections of DNA that act as instructions to make proteins. They are located along chromosomes (there are thousands per chromosome.
A gene holds the information to build & maintain cells and mass genetic traits to offspring
All body cells (somatic cells) contain the full genome (full set of genes)
One gene codes for the production of one protein
Only certain genes are working depending on the cell’s job (only certain genes are switched on)
What is the cytoskeleton
The cytoskeleton is a network of protein filaments (microtubules & microfilaments) that extend through the cytosol
(cytoskeleton) What does the protein filaments assist with?
- Generate cell movement: e.g. enable white blood cells to migrate to sites of injury. In muscle cells, they are the organelles that enable muscle contraction
- Physical support & shape: they determine the cell shape
- Cell division: they move chromosomes apart
Mitochondria
‘cell powerhouse’ - generate ATP.
Cells can contain one hundred to several thousand mitochondria, depending on the cell. Muscle cells (including those in the heart) contain the most. They use ATP to generate muscle contraction.
They are located near where oxygen enters cells or where ATP is used in the cell.
Mitochondria use oxygen & nutrients such as glucose to create ATP in a process called ‘aerobic respiration’.
They contain a double-layered membrane with fluid in between. The inner membrane has a series of folds called ‘cristae’ which produce a vast surface area for reactions.
ATP
(adenosine triphosphate) The energy currency of blood cells
Ribosomes
Ribosomes act as the sites of protein synthesis. Their name reflects the high content of ribonucleic acid (RNA)
Ribosome’s are either free/mobile (in cytoplasm) or stationary (bound to rough endoplasmic reticulum)
Free ribosomes make protein for inside the cell, whilst those on the rough endoplasmic reticulum make protein for outside the cell.
They synthesise proteins for specific organelles, which they export from the cells, e.g. hormones
Endoplasmic reticulum (ER)
The ER is a network of membranes in the form of flattened sacs
The ER extends from the nuclear envelope throughout the cytoplasm, to the cell membrane
It’s outer surface is studded with ribosomes (hence rough appearance) - Synthesises & transports proteins
Smooth ER
The smooth ER contains no ribosomes (smooth appearance). It contains unique enzymes and performs the following:
- Synthesises lipids & steroid hormones e.g. oestrogen
- In the liver, enzymes of smooth ER detoxify alcohol & drugs
- In muscle, it releases calcium for muscle contraction
Golgi Apparatus
‘The cell post office’
It modifies, sorts, packages and transports proteins received from the rough ER
It consists of flattened membranous sacs. Most cells have several Golgi Apparatuses.
A transport vesicle that buds off from the rough ER moves towards the Golgi Apparatus and releases proteins into it. Enzymes modify the proteins and they bud off in transport vesicles.
Lysosomes
They have a cell role in ‘cell digestion’
Lysosomes recycle worn out organelles; they engulf and digest these and the components are returned to the cytosol for reuse. They are digest foreign cells.
They contain as many as 60 powerful enzymes which breakdown a variety of molecules once fused with them
Lysosomes also release enzymes externally e.g. with sperm to assist egg entry
Explain mitosis
Somatic cells reproduce via mitosis - One division creating two identical daughter cells
A full set of chromosomes is first duplicated and then evenly divided into both daughter cells. The chromosomes are pulled apart by the protein filaments that make up the cytoskeleton
Purpose: growth & repair
what cells in the body cannot undergo mitosis
neurons
Meiosis
Meiosis describes the process through which gametes/sex cells are formed
Produces four haploid cells through two divisions
The four cells produced are non-identical as the chromosomes overlap (genetic variability)
Ovum
Female gamete/sex cell
Larger and immobile
Sperm
Male gamete/sex cell
smaller and mobile (due to it’s tail/flagellum)
Fertilisation (conception)
Describes the fusion of a male and a female gamete
This leads to the formation of a zygote (a diploid cell) which has two copies of each chromosome (23 pairs) - one from each parent
Mutation
A mutation describes a change in the genetic information (DNA sequence of A,T,C,G)
A mutation changes this sequence through different mechanisms, (changing the output/faulty).
Mutations in gametes (sex cells) ARE passed onto offspring.
Mutations in somatic cells can NOT be inherited.
Mutations can occur by chance or be induced by mutagenic agents, e.g. radiation smoking, vaccines
Protein synthesis
Cells use the DNA code as a template for the syntheses of a specific protein
Protein synthesis includes two phases:
1. Transcription: a copy of one gene is made into mRNA. This travels out of the nucleus to a ribosome.
- Translation: The ribosomes reads the code and produces a chain of amino acids to form the required protein.
Transport of molecules
Substances can move in & out of cells through the cell membrane
Transport of materials across the cell membrane is essential to cell life
Certain substances must move into the cell to support various functions such as metabolism & immunity, whilst substances must also be excreted from the cell.
Two main types of movement: passive transport & active transport
Passive transport
Passive transport describes the movement os substances from an area of high to low concentration (down the concentration gradient)
Requires NO energy
The three types of passive transport are:
- Diffusion
- Osmosis
- Facilitated diffusion
Explain the types of passive transport
- Diffusion: the movement of small substances from high to low concentration e.g. gases
- Osmosis: the passive movement of water
- Facilitated diffusion: the movement of larger substances (such as glucose & charged molecules) from high to low concentrations with the aid of transmembrane proteins
Active transport
Active transport describes the movement of substances from an area of low to high concentration ( up the concentration gradient)
Requires energy (ATP)
The main examples of active transport are:
- Pumps
- Endocytosis
- Exocytosis
Explain the examples of active transport
- Pumps: (e.g. sodium-potassium pump) use protein pumps in the cell membrane to allow specific molecules up the concentration gradient
- Endocytosis: engulfing of particles into the cell through cell membrane extensions
- Exocytosis: removal of waste from the cell. The material fuses with the cell membrane before being expelled
Histology
A tissue is a group of specialised cells with a similar function.
The four types of tissues are:
- Epithelial tissue
- Connective tissue
- muscular tissue
- nervous tissue
Epithelial tissue
Covers parts of the body
Cells are closely packed together
Divided into ‘covering’ or ‘glandular epithelium’
Epithelial tissue provides a selective barrier, for protection & secretion of substances
Epithelial tissue is located in blood vessels, the heart, lungs, reproductive organs, urinary tract, gastrointestinal tract (GIT), skin & eyes
Epithelial tissue: glands
A gland is a single cell or groups of epithelial cells that produce secretions. There are two types:
- Exocrine glands: Secrete their products into ducts. Secretions includes saliva, milk, sebum, sweat, enzymes
- Endocrine glands: Enter interstitial fluid and then diffuse into blood. These glands produce hormones
Connective tissue
Most abundant tissue, including bone, cartilage and blood
Connective tissues are formed of two basic elements:
- Extracellular matrix
- Cells (widely spread apart)
Extracellular matrix - connective tissue
Formed of ‘ground substance’ & ‘protein fibres’
Ground substance - is between cells and helps determine the functionality of the tissue (fluid, semi-fluid or calcified).
The protein fibres - are collagen & elastic
Cells - connective tissue
The cells are widely spaced apart unlike epithelium
-These include cells that synthesise the protein fibres (fibroblasts), white blood cells & fat cells
Connective tissue cells examples
- Fibroblasts: Large and most numerous cells. Secrete protein fibres to make collagen & elastic fibres. Active in repair & healing.
- Adipocytes: Store triglycerides (fat)
- White blood cells:
- Macrophages = engulf foreign cells (phagocytes)
- Lymphocytes = Produces antibodies
- Mast cells = release inflammatory chemicals
Collagen fibres
Made from the protein collagen
Strong fibres
Especially in bone, ligaments, tendons
Occur in parallel bundles for extra strength
Elastic fibres
Made from the protein elastin, surrounded by glycoprotein to add strength
Smaller diameter
Strong but stretchy. Allow tissue to return to original shape
In skin, blood vessel walls, and lung tissue
Connective tissue functions
- Structural framework (bone, cartilage)
- Transport nutrients & waste (blood)
- Protection for vital organs (bone, cartilage, adipose)
- Support & interconnection (tendons, ligaments, etc.)
- Insulation (adipose tissue)
- Energy store
- Production of blood & lymphatic cells (adipose tissue, bone marrow)
- Defence & repair (blood, lymph)
Membranes
Membranes in the body combine epithelial & connective tissues
Membranes are flat sheets that cover or line areas of the body
Four types of membranes in the body:
- Cutaneous membrane (the skin)
- Mucous membrane
- Serous membrane
- Synovial membrane
Mucous membrane
Line hollow organs that open to a surface of the body. They line the entire digestive tract, respiratory & genito-urinary tracts
The epithelial layer contains goblet cells that produce & secrete mucus - a slimy fluid which:
- Protects: the lining membrane from mechanical and chemical injury/drying (e.g. in the stomach)
- Traps: foreign particles in the respiratory tract (before they are removed by microscopic hairs called cilia).
Serous membranes
Line body cavities that do NOT open to the exterior
They are double layered, containing an:
- Inner ‘visceral layer’ - surrounds organs
- Outer ‘parietal layer’ - lines a cavity
(between the visceral & parietal layers lies serous fluid (enables an organ to glide freely within the cavity without friction
The THREE main serous membranes in the body
- PERICARDIUM: surrounding the HEART
- PLEURA: lining the thoracic cavity and surrounding the LUNGS
- PERITONEUM: lining the abdominal cavity and surrounding ABDOMINAL ORGANS (and some pelvic organs)
Synovial fluid
The synovial membranes contain cells called ‘synoviocytes’, which secrete synovial fluid
Synovial fluid lubricates & nourishes the moveable joint cavities which it bathes
Aerobic respiration equation
(glucose) + oxygen → carbon dioxide + water + ATP
Body favours using glucose, but could also use fatty acids and as a last resort amino acids (proteins)
Carbon dioxide & water are a byproduct of creating ATP
steroid hormones are known as what?
lipid based hormones
DNA consists of various sequences of four amino acids what are they are what are their pairs?
A, T, C, G
Pairs: (A+T) (C+G)
