Module 1: Cells Flashcards
What are the six levels of structural organization?
Chemical level, cellular level, tissue level, organ level, system level, organismal level
What is the chemical level of organization?
These are the building blocks of the body. It includes atoms and their joining to form molecules.
What is the cellular level of organization?
These are the basic structural and functional units of the body. There are approx. 200 types. Eg. Cardiac muscle cells.
What is the tissue level of organization?
Tissues are groups of cells and materials surrounding them which work together to perform a function. Eg. Cardiac tissue.
What are the four main classes of tissues?
Epithelial, connective, muscular, nervous
What is the organ level of organization?
These are structures with specific functions made up of two or more types of tissue. They tend to have recognizable shapes. Eg. the heart.
What is the system level of organization?
Systems are made up of related organs with a common function. Eg. the respiratory system
What is the organismal level of organization?
All parts of an organism functioning together to constitute the whole. Eg. the individual
What are the eleven body systems?
Integumentary Skeletal Muscular Immune Endocrine Cardiovascular Respiratory Digestive Urinary Reproductive Nervous
What are the major components of the Integumentary system?
The skin, sweat glands, hair, nails, oil glands.
What is the function of the integumentary system?
Temperature regulation, protection, production of Vit D, waste elimination, sensory, fat storage, insulation.
What are the skin’s 3 parts and their functions in the integumentary system?
Cutaneous membrane: Protection
Epidermis: Vit D production
Dermis: Feeds epidermis, strength, contains glands
What are the hairs’ 3 parts and their functions in the integumentary system?
Hair follicle: Produces hair. Connects to nerves so provides sensation.
Hair: Protection
Sebaceous glands: lubricates hair shaft and epidermis
What is the sweat glands’ function in the integumentary system?
Regulation of temperature. NB breast tissue counts as modified sweat gland tissue
What is the nails’ function in the integumentary system?
Stiffen and protect digits
What is the sensory receptors’ function in the integumentary system?
Detect sensations (touch, pressure, temperature, pain)
What is the hypodermis’s function in the integumentary system?
Stores fat, attaches skin to deeper layers
What are the major components of the muscular system?
Skeletal muscles, Axial muscles, Appendicular muscles, tendons, aponeuroses
What is the function of the skeletal muscles in the muscular system?
Allow for movement, control entry and exit of digestive/urinary systems, produce heat, support skeleton, protect soft tissues
What is the function of the axial muscles in the muscular system?
Support and position axial skeleton (head and trunk of organism)
What is the function of the appendicular muscles in the muscular system?
Support, move and brace the limbs
What is the function of the tendons in the muscular system?
Wire muscles to bones, convert contractile forces of muscles to movement
What is the function of the aponeuroses in the muscular system?
Form connections between muscles, convert contractile forces of the muscles to movement
What is the function of the muscular system?
Movement, posture and heat production
What are the major components of the skeletal system?
Bones, joints, cartilage, axial skeleton, appendicular skeleton, red and yellow bone marrow.
What is the function of the skeletal system?
Support and protection, area for muscle attachments, movement, production of blood cells, store minerals and fats.
What is the function of the axial skeleton in the skeletal system?
Protects brain, spinal cord, sense organs, thorax. Supports body weight over lower limbs
What is the function of the appendicular skeleton in the skeletal system?
Internal support/positioning of limbs, support and move axial skeleton.
What is the function of the red/yellow bone marrow and what is the relationship between them?
Red produces red blood cells, found in flat bones. Yellow stores fat cells. Found in the medullary cavity and long bones. Also stores minerals. As we age, we lose red and gain yellow bone marrow.
What are the major components of the nervous system?
Brain, spinal cord, sense organs, central and peripheral nervous systems
What is the function of the nervous system?
Generates nerve impulses (action potentials) to control activities, detects changes in in/external environments and responds
What is the function of the brain in the nervous system?
Complex integrative activities, controls voluntary vs involuntary
What is the function of the spinal cord in the nervous system?
Relays information to/from brain. Less complex integrative activities
What is the function of the sensory organs in the nervous system?
Sensory input to brain (light, sound, smell etc.)
What is the function of the CNS and PNS in the nervous system?
CNS is the control center, and can have short term control over other systems. PNS links CNS with other systems and sense organs
What are the main components of the cardiovascular system?
Heart, blood, blood vessels
What is the function of the cardiovascular system?
Pump blood throughout body, remove cell waste, regulate pH, temperature, H2O conc, defence, repair damaged blood vessels
What is the function of the heart in the cardiovascular system?
Propels blood around body and maintains BP
What is the function of the blood in the cardiovascular system?
Transport of O2, CO2, minerals and hormones Waste removal Temperature regulation Defence pH balance
What are the functions of the 3 types of blood vessels in the cardiovascular system?
Arteries: Carries oxygenated blood from heart to capillaries
Veins: Carries deoxygenated blood from capillaries to heart
Capillaries: Site of diffusion between blood and interstitial fluids
What are the main components of the lymphatic system?
Lymphatic fluid and vessels, lymph nodes and tonsils, spleen, thymus
What is the function of the lymphatic system?
Returns fluid and proteins leftover from capillary diffusion to blood. Lipids from gastrointestinal tract to blood. Maturation of B and T cells to protect against pathogens
What is the function of the Lymphatic fluid and vessels in the lymphatic system?
Carry lymph (water and protein) and lymphocytes from outer tissues to CV system. Same with lipids from the gut
What is the function of the lymph nodes/ tonsils in the lymphatic system?
Monitor composition of lymph, engulf pathogens, stimulate immune response
What is the function of the spleen in the lymphatic system?
Monitors circulation blood cells
Engulfs pathogens
Recycle red blood cells
Stimulate immune response
What is the function of the thymus in the lymphatic system?
Controls development/maintenance of T cell lymphocytes
What are the major components of the reproductive system?
Gonads (testes and ovaries) and associated organs (fallopian/uterine tubes, uterus, vagina and mammary glands, epididymus, ductus/vas deferens, seminal vesicles, prostate and penis)
What is the function of the reproductive system?
Production of gametes (and ultimately new organism). Production of hormones, transport and storage of gametes, milk production (females)
What is the function of the gonads in the reproductive system?
Produce gametes (sperm or oocytes)
What is the process of sperm’s development?
Vans deferens transports immature sperm to epididymis. This combines with seminal fluid produced by the prostate and seminal vesicle before being ejaculated through the urethra.
What is the purpose of the external genitalia of males (penis and scrotum)?
Reproduction and thermoregulation of testes
What is the function of the fallopian tubes?
Location of fertilisation. Delivery of oocyte
What is the function of the uterus in the reproductive system?
Site of embryonic development
What is the function of the vagina in the reproductive system?
Lubrication, sperm reception and birth canal
What is the function of the mammary glands in the reproductive system?
Nutrition for offspring
What are the major components of the urinary system?
Kidneys, bladder ureters and urethra
What is the purpose of the urinary system?
Produces, stores and eliminates urine. eliminates waste and regulates chem. composition of the blood. pH of body fluids, mineral balance, prod. of red blood cells.
What is the function of the kidneys in the urinary system?
Form and concentrate urine
Regulate pH
Endocrinal function (produces red blood cells)
What is the function of the ureters in the urinary system?
Conduct urine to bladder
What is the function of the urinary bladder in the urinary system?
Stores urine before elimination
What is the function of the urethra in the urinary system?
Conducts urine to exterior
What are the major components of the respiratory system?
Nasal cavity, larynx, pharynx, trachea, bronchial tubes, lungs
What is the purpose of the respiratory system?
Gas exchange, pH balance, production of sounds
What is the function of the nasal cavity in the respiratory system?
Filter, warm, humidify air. Detect smell
What is the function of the pharynx in the respiratory system?
Conducts air to larynx
What is the function of the larynx in the respiratory system?
Protects opening to trachea, contains vocal chords
What is the function of the trachea in the respiratory system?
Filters air. NB it is kept open by cartilage
What is the function of the Bronchial tubes in the respiratory system?
Conducts air between trachea and lungs
What is the function of the lungs in the respiratory system?
Air movement, gas exchange, pH control
What are the major components of the endocrine system?
Hormone producing glands (Pineal, hypothalamus, pituitary, thymus, thyroid, parathyroid, adrenal) pancreas, kidneys, gonads
What is the purpose of the endocrine system?
Regulate body activities by release of hormones
What is the function of the pineal gland?
Reproduction timing, day/night rhythms
What is the function of the pituitary gland?
Controls other endocrine glands. Controls growth, keeps fluid balance
What is the function of the thymus?
Maturation of lymphocytes
What is the function of the thyroid gland?
Controls metabolic rate and calcium levels
What is the function of the parathyroid gland?
Controls Ca levels
What is the function of the adrenal gland?
Water balance, cardio and respiratory functions, tissue metabolism
What is the function of the pancreas in the endocrine system?
Glucose control
What is the function of the kidneys in the endocrine system?
Produces red blood cells, raises blood pressure, controls Ca levels
What is the function of the gonads in the endocrine system?
Code for sexual characteristics and reproduction
What are the major components of the digestive system?
Oral cavity, salivary glands, oesophagus, pharynx, stomach, small and large intestine, pancreas, gall bladder, liver, anus
What is the purpose of the digestive system?
Physical and chemical breakdown of food. Absorbs nutrients and eliminates solid waste
What is the function of the oral cavity in the digestive system?
Mechanical digestion- teeth and tongue
What is the function of the salivary glands in the digestive system?
Buffers and lubricant, production of enzymes (chemical breakdown)
What is the function of the pharynx in the digestive system?
Solid food and liquid to oesophagus. Chamber shared with trachea
What is the function of the oesophagus in the digestive system?
Deliver food to stomach
What is the function of the stomach in the digestive system?
Enzyme production and acid for chem breakdown
Muscular contractions for mechan breakdown
Produces hormones
What is the function of the small intestine in the digestive system?
Buffers and hormones
Digestive enzymes
Absorption of nutrients
What is the function of the large intestine in the digestive system?
Water removal, waste storage and removal
What is the function of the pancreas in the digestive system?
Endocrine cells, enzymes, buffer
What is the function of the liver in the digestive system?
Produces bile, regulates nutrients in blood
What is the function of the gallbladder in the digestive system?
Stores, concentrates and secretes bile
What is EPO?
Erythropoietin is a glycoprotein hormone produced by the kidneys. It signals for erythropoiesis in the bone marrow. A red blood cell stem cell is affected, causing more RBC production and greater O2 carrying ability in the blood
What is epithelial tissue?
Tissue that covers body surfaces, lines hollow cavities, ducts and organs and forms glands
What are the functions of epithelial tissue?
Protection, secretion, filtration, absorption, excretion
What is muscular tissue?
Contractile cells (eg muscle fibres)
What are the functions of muscular tissue?
Movement, heat generation
What is connective tissue?
Cells in a matrix which connect, support and protect organs while distributing blood vessels to other tissue
What is the function of connective tissue?
Protection, support, binds organs together, stores energy, transports blood
What is nervous tissue?
Conducting nerve cells and supporting neuroglia
What is the function of nervous tissue?
Detects changes and generates impulses
What are germ layers?
These produce the tissue types. All four are produced from the layers
What are the different germ layers?
Ectoderm, endoderm and mesoderm
What tissues are formed from the ectoderm germ layer?
Epithelial, nervous
What tissues are formed from the mesoderm germ layer?
Epithelial, connective, most muscle
What tissues are formed from the endoderm germ layer?
Epithelial
Describe epithelial tissue
Contains lots of cells tightly packed
Little/no extracellular matrix
Almost always the outermost layer (not covered by other tissue)
Avascular
Found next to blood-rich tissue as it needs a supply of nutrients and O2, with removal of CO2
Consists of cells in sheets with one or more layers
Has a high rate of mitosis as freq. damaged
Can combine with nervous tissue to form sensory organs
How does epithelial tissue act as a barrier?
Controls transfer of substances in/out of body
Secretes products onto its free (apical) surface
It also acts as a protective barrier
What is an apical surface?
A side of the cell which doesn’t touch other tissue
What is a lateral surface?
The sides of the cells facing other cells, and the site of cell junctions
What is a basal surface?
Opposite of apical surfaces- the bottom side of the cell. In the lowest epithelial cells these are connected to the basement membrane.
What is the basement membrane and what is it made up of?
Extracellular barrier between epithelial and connective tissue. Forms a site of migration for epithelial cells when tissue is damaged. Controls movement of large molecules between the two tissues, acts in blood filtration in the kidneys. Made up of basal lamina and reticular lamina. NB transport occurs by diffusion.
What is the basal lamina?
A layer of basement membrane closer to and secreted by the epithelial cells. It contains proteins (laminum and collagen) and attaches the epithelial cells to the basement membrane.
What is the reticular lamina?
A layer of the basement membrane closer to the connective tissue cells. It contains proteins and is produced by the fibroblasts in the connective tissue.
What are the different possible arrangements of covering epithelial cells?
Simple: Single layer (FADOS)
Pseudostratified: Single layer appearing to be many due to long cells and scattered nuclei. Only some cells have apical surface but all reach BM. Has goblet cells.
Stratified: Many layers, best for protecting surfaces
What are the different possible shapes of covering epithelial cells?
Squamous: Flat and thin for rapid transport
Cuboidal: Cube shaped with microvilli at apical surface. Good for secretion/absorption
Columnar: Rectangular. Good for protecting underlying tissue. Can have cillia/microvilli
Transitional: Changes from squamous to cuboidal to accommodate stretch- eg. bladder
What are simple squamous cells?
A single layer of flattened cells with centralized nuclei
Where are simple squamous cells found?
In the lining of the cardiovascular and lymph systems, where it is known as endothelium. It also forms a layer in the serous membranes (pleura, pericardium, peritoneum) where it is known as the mesothelium. Also air sacs, bowman’s capsules and the eardrum
What is the function of simple squamous cells?
Filtration, secretion, diffusion. Not good for protection as it is so thin.
What are simple cuboidal cells?
A single layer of cube shaped cells with centralized nuclei
Where are simple cuboidal cells found?
Lens surface, pancreatic and kidney ducts, pigmented at the back of the retina, ovary surface, secretary portion of glands (eg thymus)
What is the function of simple cuboidal cells?
Secretion and absorption
What are non-ciliated simple columnar cells?
Single layer of column shaped cells with the nuclei near the base. Some have microvilli which inc. SA:V ratio so inc. rate of absorption. Goblet cells secrete mucus at the apical surface.
Where are non-ciliated simple columnar cells found?
They line the gastrointestinal tract, ducts of many glands and the gallbladder
What is the function of non cilliated simple columnar cells
Goblet cells: Secretion and lubrication. Microvilli’d- absorption The secretion helps prevent damage to the delicate tracts they line.
What are ciliated simple columnar cells?
Single layer of cells with the nuclei near the base. They have cilia and goblet cells
Where are ciliated simple columnar cells found?
Bronchioles, fallopian tubes, sinuses, central canal of spinal cord, ventricles of brain
What is the function of ciliated simple columnar cells?
Their cilia beat together to move objects (eg. eggs) for expulsion or transport. Columnar cells are better for secretion than cuboidal as they are larger and so can have more organelles.
What are stratified squamous cells?
Multiple layers of cells- the outer layers are flatter, increasing to more cuboidal shaped deeper down. Outer cells tend to be hardened and tough due to dehydration (moved further from the blood supply). There are both keratinized (hard and tough re. dehydration) and non keratinized (soft due to external moistening) varieties
Where are stratified squamous cells found?
K: Skin.
NK: Lines wet surfaces- tongue, vagina, oesophagus, pharynx, anus.
What is the function of stratified squamous cells?
Protection against abrasion and dehydration. Protects against the entry of microbes. They tend to be found where mechanical and chemical stress levels are high.
What are pseudostratified columnar cells?
A single layer of rectangular cells with the nucleus at varying heights. There are ciliated and non ciliated varieties, as well as those with goblet cells. All reach the BM, but not all have an apical surface
Where are pseudostratified columnar cells found?
Ciliated: Lines upper respiratory tract.
Non Ciliated: Large ducts of glands, epididymus, part of the urethra
What is the function of pseudostratified cells?
C: Secrete and move mucus
N: Absorption and protection
What are stratified cuboidal cells?
Many layers of cube shaped cells
Where are stratified cuboidal cells found?
Sweat glands, oesophageal glands, urethra
What is the function of stratified cuboidal cells?
Protection, some secretion and absorption
What are stratified columnar cells?
Layers of rectangular shaped cells
Where are stratified columnar cells found?
Lining of the urethra, large excretory ducts of glands, eye, anal membrane
What is the function of stratified columnar cells?
Protection and secretion
What are endocrine glands?
Glands that secrete substances directly into the bloodstrem
What are exocrine glands?
Glands that secrete substances onto a free surface to be absorbed or moved
What is an example of a unicellular gland?
A goblet cell. The apical cytoplasm contains large secretory vessicles
What are the different duct structures?
A gland is simple if the duct does not split, and complex if it does.
What are the different structures of the secretary areas?
Tubular, alveolar, tubuloalveolar, (coiled, branched for simple only)
Where are simple tubular glands found?
Interstitial glands
Where are simple coiled glands found?
Sweat glands
Where are simple branched glands found?
Gastric glands, mucous glands of oesophagus, tongue, duodenum
Where are simple alveolar glands found?
Stage in embryo development of SBTs
Where are complex tubular glands found?
Sebaceous glands
Where are complex alveolar glands found?
Mammary glands
Where are complex tubuloalveolar glands found?
Salivary glands, glands of respiratory passages, pancreas
What are merocrine glands?
Glands which form substances with ribosomes on rough er, then processed by golgi bodies, and secreted by exocytosis
What are apocrine glands?
Secretion accumulated on apical surface of cell, which then pinches off via exocytosis. Cell repairs/repeats
What are holocrine glands?
Accumulate secretion in cytosol. Cell ruptures, releasing secretion. Cell dies and is replaced
What is a tight junction?
Join cytoskeletons of adj. cells by strings of protein wrapping around (spec. Claudins and Occludin). These prevent the movement of ions and protons between the cells, maintaining cell polarity. The more strands there are, the more strong the junction.
What are adherens junctions?
An adherens belt goes all the way around cells. This is made of plaque and actin. Cadherins (C-Adherins) links the actin in different cells’ belts together, bridging the gap between them. This prevents the cells from separating during movement.
What is a desmosome junction?
These resist shearing forces. The Cadherin attaches to keratin fibres on the plaque belt, forming a bridge between the cells.
What is a hemidesmosome?
Like half a desmosome, only found on the basal surface of the cells. A protein calls lamina links the keratin in the cells to the basal membrane.
What is a gap junction?
This is a direct connection between cells formed by connexons. Connexons are made of 6 connexins coming together to form a tunnel like structure. They can close and open, and have openings on both sides of the bridge. small molecules and ions can transfer through.
What is the function of connective tissue?
Protection, immune support, Fat storage (for Energy), Binding and Support. Transport is also achieved through the blood.
What is connective tissue made up of?
Cells, and an extracellular matrix containing ground substance and fibres
What are the different cells of the connective tissue?
Fibroblasts, Macrophages, plasma cells, mast cells, leukocytes and adipocytes
What are fibroblasts?
Large flat cells which secrete fibres and ground substance
Where are fibroblasts found?
They migrate through all general connective tissue
What are macrophages?
They develop from monocytes, have an irregular shape with branching projections. They destroy bacteria and debris by phagocytosis (engulfing)
Where are macrophages found?
Fixed: Stay in a certain type of tissue (eg. lung tissue)
Wandering: Move throughout the body but gather at infection sites
What are plasma cells?
Small cells developed from b. lymphocytes. They secrete antibodies to attack foreign substances
Where are plasma cells found?
Gastrointestinal tract, respiratory tract, salivary glands, lymph noes, spleen and red bone marrow
What are mast cells?
They produce histamine (dilates small blood vessels). They can bind to, ingest and kill bacteria.
Where are mast cells located?
They are abundant alongside blood vessels supplying connective tissue
What are adipocytes?
They are fat cells
Where are adipocytes found?
They are deep beneath the skin and surround organs
What are leukocytes?
White blood cells which instigate immune responses
Where are leukocytes found?
Not normally in connective tissue however: eosinophils move to the sites of parasitic infection and neutrophils move to general infection sites.
What is the difference between a -blast and a -cyte?
Blast is immature, Cyte is mature
What is ground substance?
It can be fluid, semifluid, gelatinous or calcified.
It supports and binds cells, stores H2O and is a medium for substance exchange.
It fills the spaces between connective cells
What is ground substances made up of?
Glycosaminoglycans (GAGs) which can be either sulfated or non sulfated. Also water and proteins such as fibronectin to link ground substance components together
What are the sulfated GAGs and where are they found?
Chondroitin sulfate: cartilige, bone, skin, blood vessels
Dermatan sulfate: Skin, tendons, blood vessels, heart valves
Keratan Sulfate: Bone, cartilage, cornea
What is the non sulfated GAG and what is its function?
Hylauronic acid binds cells together and lubricates joints. It is broken up by hylaurondase.
What do the GAGs do?
Trap water to increase viscosity of ground substance. Also support and adhesion for cells
What are the different fibres and what is their general purpose?
Collagen, elastic and reticular: they strengthen and support connective tissue
What is Collagen fibre?
Strong but flexible, often occurring in parallel bundles to increase tensile strength.
Where is collagen fibre found
Bone, cartilage, tendons, ligaments.
What is elastic fibre?
Smaller than collagen, and comes together to form a fibrous network. They are strong but stretchy and return to their original shape (elasticity). They are made of elastin (protein) and fibrolin (glycoprotein) for strength.
Where is elastic fibre found?
Skin, blood vessel walls and the lungs
What is reticular fibre?
Made up of collagen, but in finer bundles with a coat of glycoprotein. They support blood vessels walls and form networks. They are produced by fibroblasts. They are thin and branching
Where are reticular fibres found?
Stroma of soft organs (eg. spleen). Part of the basement membrane
What is the embryonic connective tissue?
Mesenchyme: Irregularly shaped mesenchymal cells in a semifluid ground substance. It contains delicate reticular fibres
Where is embryonic connective tissue found?
In the embryo, under the skin and along its developing bones. Some remains in adults’ blood vessels.
What is the function of mesenchyme?
It forms almost all other connective tissue
What are the types of loose connective tissue (arranged loosely between cells)
Areolar, Adipose and reticular
What is areolar loose connective tissue?
Widely spread. Made up of all fibres and connective cells in a semifluid ground substance- like packing material
Where is areolar loose connective tissue found?
Nearly everywhere
What is the function of loose areolar connective tissue?
Strength, elasticity and support
What is adipose loose connective tissue?
Made from fibroblasts. Stores fats. Two types- brown and white. Brown is more vascular, white has fewer. As more fat cells develop, more blood vessels appear
Where is adipose tissue found?
With areolar. Particularly the skin, surrounding heart and kidneys, yellow bone marrow and joint padding.
What is the function of adipose tissue?
Fat storage- energy reserves and insulation. Support, protection and temperature control
What is reticular loose connective tissue?
Interlacing network of reticular fibres and cells
Where is reticular loose connective tissue found?
Stroma of liver, spleen, lymph nodes. Red bone marrow, reticular lamina, surr. blood vessels and muscles
What is the function of reticular tissue?
Binds smooth muscle and tissue cells, filters and removes old blood cells
What is dense connective tissue?
Fewer cells with more fibres
What are the types of dense connective tissue?
Regular, irregular and elastic.
What is regular connective tissue?
Has shiny white extrac. matrix. Regularly arranged collagen fibres, with fibroblasts in between. It heals slowly as collagen is non living
Where is regular connective tissue found?
Tendons, ligaments and aponeuroses
What is the function of regular connective tissue?
Strong attachments as withstands pulling along fibres
What is irregular connective tissue?
Irregularly arranged collagen fibres with few fibroblasts.
Where is irregular connective tissue found?
In sheets (eg. in fasciae (tissue under the skin surrounding muscles and organs)), deep region of dermis, membrane capsules and joint capsules
What is the function of irregular tissue?
Tensile strength in many directions
What is elastic dense connective tissue?
Contains elastic fibres with fibroblasts
Where is elastic tissue found?
Lungs, arteries, some ligaments, vocal chords, trachea, bronchioles
What is the function of elastic tissue?
Allows stretching and recoil
What is cartilige connective tissue?
Made of collagen and elastic fibres, with a chondroitin sulfate ground substance. It is strong and resilient with no nerves or blood vessels. Mature cells (chondrocytes) occur in groups called lacunae in the extrac. matrix. Dense conn, irregular surrounds most cartilage called the perichondrium- it’s the source of new cells. It heals poorly as it is avascular.
What is the function of cartilage connective tissue?
Support and embryonic growth
What are the two ways in which cartilage connective tissue can grow?
Interstitial or appositional
What is interstitial growth?
Existing cells divide and secrete more matrix, pushing them apart and causing the tissue to expand. Occurs in early childhood to adolescence
What is appositional growth?
Inner perichondrium becomes chondroblasts. These surround themselves with matrix and become chondrocytes. Matrix accumulates and the cartilage widens.
What are the different types of cartilage connective tissue?
Hyaline, fibrocartilage and elastic
What is hyaline tissue?
Gel as ground substance, fine collagen. Chondrocytes found in lacunae
Where is hyaline tissue found?
Mostly in cartilage at the end of long bones outer ribs, nose, larynx, trachea, bronchi and tubes and fetal skeleton
What is the function of hyaline tissue?
Smooth surface for joint movement, flexibility and support. Can be fractured as it is weak
What is fibrocartilage tissue?
No perichondrium, chondrocytes arr. in lacunae
Where is fibrocartilage found?
Pubic symphyses, vertebral discs, knees, tendons
What is the function of fibrocartilage?
Support and join structures. It is strong and rigid
What is elastic cartilage tissue?
Chondrocytes float in a network of elastic fibres
Where is elastic cartilage tissue?
Epiglottis, external ear, auditary tubes
What is the function of elastic cartilage tissue?
Strength and elasticity allows it to maintain structures’ shapes
How is compact bone organized?
It is made up of osteons. These contain:
Lamellae: Rings of extracel matrix comprised of mineral salts (Ca, P) and collagen fibres. This makes bones strong and hard
Lacunae: Spaces between lamellae where osteocytes are housed
Canaliculi: Networks of tiny channels connecting osteocytes. Routes for nutrition and waste removal
Central canal: houses blood vessels and nerves
How is spongy bone organized?
Made up of bone columns (trubeculae) containing lamellae, osteocytes, lacunae and canaliculi
Spaces between produce red bone marrow
What is the function of bone tissue?
Support, protection, fat storage, blood formation and movement
How are osteocytes formed?
Start as osteogenic cell from mesenchyme which becomes trapped. Becomes osteoblast, a bone forming cell. It produces bone and encases itself, becoming trapped and losing some organelles and therefore function. Finally it becomes and osteocyte, which manages blood tissue. Gap junctions allow them to communicate
What is an osteoclast?
A multinucleated cell which breaks down bones to produce Ca and P. Allows production of new bone.
What is marfan Syndrome?
Caused by a mutation of Chromosome 15, coding for fibrolin. It causes deformed elastin.
Symptoms are tall height with very long feet and fingers.
Elastic properties of blood vessels don’t work properly. This can cause blood not to be fully passed through valves, causing a bulge in the vessel. If this bursts it causes an aneurysm, which could cause death
What are the types of liquid connective tissue?
Blood and lymph
What is blood?
Liquid containing plasma (water with diss hormones, nutrients) white blood cells, red blood cells and platelets
Where is blood found?
Blood vessels and heart
What is the function of blood?
Co2/O2 transport, immune response, clotting
What is lymph?
Extracellular fluid. Several types of cell in a clear extracellular matrix
Describe the makeup and function of general muscle tissue
Consists of long cells called muscle fibres/myocytes. They use ATP to generate force via hydrolysis. This is done for movement, posture and heat production.
Describe skeletal muscle
Long cylindrical fibres with striations. Multinucleated, with nuclei on the periphery of cells. Called ‘voluntary muscle’ as it can be made to flex or relax consciously. NB doesn’t always have to be voluntary eg. posture
Where is skeletal muscle located?
Attached to bones via tendons
What is the function of skeletal muscle?
Motion, posture, heat and protection
Describe cardiac muscle
Branched, striated cells with 1-2 central nuclei. Jointed together through INTERCALATED DISCS. These contain desmosomes (for strength) and gap junctions (to pass electrical signals).
Where is cardiac muscle located?
The heart wall
What is the function of cardiac muscle?
Pumps blood around the entire body
Describe smooth muscle
Non striated fibres shaped into spindles with a single central nucleus. Gap junctions between cells cause them to contract simultaneously. Where no gap junctions are present cells contract individually.
Where is smooth muscle located?
Iris of eye (without GJs) Hollow internal structures (eg. blood vessels)
What is the structure of smooth muscle?
They have thick filaments (myosin) and thin filaments (actin). These attach to dense bodies above and below. Dense bodies are interconnected by intermediate fibres. These do not stretch, so when the muscle contracts it must squeeze.
What are the different layers inside of skeletal muscle and the structure of them?
Muscles contains many fasicles. The fasicles contain muslce fibres (myocytes). The fibres in turn contain myofibrils. Skeletal muscle is surrounded by connective tissue.
What are fascia?
A type of dense irregular connective tissue which surrounds and binds muscle fibres together. This allows for free movement, carries nerves, blood and lymph vessels.
What is the function of the hypodermis in relation to skeletal muscle?
Connects muscle to skin, provides blood supply, nerve endings and fat storage.
What is the epimysium?
Surrounds the whole muscle (Dense irregular connective tissue). Has a shiny exterior. Cannot expand.
What is the perimesium?
Surrounds groups of 10-100 fibres, grouping them into fasicles.
What is endomesium?
Reticular fibres inside the fasicles which separate muscle fibres.
How are muscle fibres made up?
Most of the muscle fibres are made up of myofibrils. These run the length of the muscle. They are comprised of two different myofilaments: thin (made of actin) and thick (made of myosin). These are the contractile portions of the muscle. They do not run the length of the muscle, but are separated into sarcomeres.
What are striations?
Banding in the cardiac and skeletal fibres. They are caused by the joining of thick and thin filaments, which overlap in some portions and not in others
What is the A band?
The dark part of the striation, running the length of the thick filaments
What is the I band?
The light part of the striation, where there are only thin filaments
What is the H zone?
A subset of the A band comprising only of thick filaments
What is the M line?
The middle of the sarcomere, holding the thick filaments together. This gives the sarcomeres their structures.
What are Z discs?
The centre of the I bands, between sarcomeres. These join sarcomeres together and are comprised of actin.
How are thick filaments (myosin) arranged?
Like twisted golf clubs with handletops at the M line. The heads point to six surrounding thin filaments
How are thin filaments (actin) arranged?
These anchor to Z discs and are mainly comprised of actin in a helix with binding sites for myosin.
What makes up nervous tissue?
Neurons and Neuroglia
What is the function of neurons?
Convert stimuli to NAPs to convey around the body
What is a neuron made up of?
Cell body, dendrites and axon
What is neuroglia important for?
Support and maintenance of neurons.
What is a NAP and how do they move?
Nerve Action Potential- an electrical signal that travels along the neurons’ surface membranes. This occurs due to ions moving in interstitial fluid and channels in the membranes of the neurons.
What does a neuron’s cell body consist of?
Nucleus, cytoplasm, lysosome, mitochondria, golgi bodies. They also contain nissl bodies (floating rough er and ribosomes). Nissl bodies carry out protein synthesis. They have neurofibrils (bundles of filaments for shape and support) and microtubules (move materials between axons and cell bodies)
What are dendrites?
The receiving portions of the cell. They are short and tapering with many branches. They have multiple receptor sites and also contain cytoplasm with nissl bodies mitochodria etc.
Describe axons
Long, thin, cylindrical projections. They join to the body of the cell at a cone shaped site called the axon hillock. The part of the axon nearest the cell body is the initial segment. It contains mitochondria, microtubules, neurofibrils, but has no Er so can perform no protein synthesis. Side branches called axon collaterals branch off at right angles. These divide further into axon terminals.
What is the function of axons?
They create nerve impulses. These start in the trigger zone- the space between the axon hillock and the initial segment. Communication occurs at the synapses, which are at the ends of axon terminals and come in bulbous or varicosites (bumps). They also contain a neurotransmitter.
Describe multipolar neurons
Two or more dendrites, with one axon. These are common in the CNS. All motor neurons are multipolar.
Describe bipolar neurons
1 dendrite (which can branch out) and 1 axon. The cell body is located in between the two. They are small and rare, found in the special sense organs
Describe unipolar neurons
The dendrite and axon is continuous with the cell body branching off to the side. The axon begins where the dendrites converge. Found in sensory nerve and are very long.
What is neuroglia?
Supportive cells which are smaller than neurons. They can divide and communicate, but not send impulses. They keep the physical structure of nerve tissue, repair nerve tissue, do phagocytosis, supply nutrients to the neurons and regulate the interstitial fluid in nervous tissue
What are the four types of neuroglia in the CNS?
Astrocytes, Ogliodendrocytes, Microglia and Ependymal
Describe astrocytes
Star shaped cell with microfilaments. Most numerous in nervous tissue
What is the function of astrocytes?
Support and repair neurons, communicate with neurons via gliotransmitters. They regulate the neurons’ environments via ion regulation. They maintain the blood brain barrier via endothelium as they can influence its permeability.
Describe ogliodendrocytes
similar to astrocytes but smaller and simpler
What is the function of ogliodendrocytes?
Insulation- they form insulating myelin sheaths around CNS axons. One cell can do more than one axon. They also accelerate NAPs
What is microglia?
Small, slender processes which perform phagocytosis on debris and damaged tissue
Describe ependymal cells
They are single cuboidal/columnar cells with microvilli and cilia. They are found lining the brain ventricles and the central canal of the spinal cord
What is the function of ependymal cells?
They produce, monitor and assist in the circulation of Cerebral Spinal Fluid
What are the two neuroglia in the PNS?
Schwann cells and satellite cells
Describe schwann cells
Small cells which encircle PNS axons
What is the function of schwann cells?
Myleinates single axon for insulation, or can support up to 20 without myleinating. They also participate in axon regeneration
What are satellite cells?
They surround the PNS cell bodies, and regulate the exchanges of materials between interstitial fluid and cell bodies. They look after the PNS cell environment.
What is the diference between protoglycans and glycoproteins?
Both are molecules containing protein and sugar. However, protoglycans contain more sugars whereas glycoproteins contain more proteins.
