BIOSCI 107 Cells and Tissues

Eleven Body Systems

Muscular

Cardiovascular

Skeletal

Endocrine

Lymphatic

Integumentary

Respiratory

Reproductive

Digestive

Nervous

Urinary

Six levels of structural organization - \####- Chemical Level

Chemical

Cellular

Tissue

Organ

System

Organisimal

Chemical level

*Building blocks* of the body

Made up of atoms and molecules

Cellular Level

Basic structural and *functional units* of the body

Tissue Level

*Groups of cells* that form together and have a *particular function*

Organ Level

*Groups of tissues* together that form together with a *specific function*

Organs are made of two or more types of tissue

System Level

*Groups of related organs* that work together with a common function

Organismal Level

*All the 11 systems* function together to create a living organism

Four basic tissue types

Epithelial

Connective

Muscle

Nervous

Components of Integumentary system

\- Cutaneous membrane (epidermis, dermis) \n - Subcutaneous membrane (hypodermis) \n - Hair follicles (shaft, sebaceous glands) \n - Sweat glands \n - Nails \n - Sensory receptors

Functions of Integumentary system

\- Cutaneous membrane (epidermis, dermis) \n - Subcutaneous membrane (hypodermis) \n - Hair follicles (shaft, sebaceous glands) \n - Sweat glands \n - Nails \n - Sensory receptors

Components of Muscular system

\- Skeletal Muscles (axial, appendicular) \n - Tendons \n - Aponeuroses

Functions of Muscular system

\- Produce heat \n - Support skeleton \n - Protect soft tissues \n - Turn contractile force into tasks (T&A)

Aponeuroses

\- Turn contractile force into tasks \n - pearly white sheet like fibrous membrane \n - Connects muscle together

Components of Skeletal system

\- Bones \n - Cartilage and Joints \n - Axial Skeleton (inc. cartilages, ligaments) \n - Appendicular Skeleton (inc. cartilages, ligaments) \n - Red bone marrow \n - Yellow bone marrow

Functions of Skeletal system

\- Axial skeleton: protects organs and soft tissues, supports body weight \n - Appendicular skeleton: internal support and enable muscle to move the axial skeleton \n \n - Red blood cell production (flat-RBM-lose with aging) \n - Storage of fat cells and mineral (long-YBM-gain with aging, though after serious injury turns to RM)

Components of Nervous system

Central nervous system (CNS): brain, spinal Chord and special senses \n Peripheral nervous system (PNS): special senses (not optic), everything outside of the brain & spinal chord

Functions of Nervous system

\- Short term control over other systems (spinal cords relays information to and from brain) \n - Sensory input e.g. smell and taste

Components of Cardiovascular system

\- Heart \n - Blood vessels (arteries, veins, capillaries) \n - Blood

Functions of Cardiovascular system

\- Propels blood and maintains blood pressure \n - Transport cells and dissolved material (blood) \n - Transport hormones \n - Thermoregulation \n - Acid base balance

Components of Lymphatic system

\- Lymphatic Vessels (efferent, afferent, capillaries) \n - Lymphatic ducts \n - Lymph Nodes \n - Spleen \n - Thymus \n - Lymph

Functions of Lymphatic system

\- Defense against infectious diseases \n - Monitor composition of lymph \n - Collects and carries lipids from guts \n - Absorbs interstitial fluid (capillaries) \n - Recycle blood cells (Spleen) \n - Controls development and maintenance of T lymphocytes (Thymus)

Components of Reproductive: Male system

\- Testes (sperm production) \n - Epididymus (sperm maturation) \n - Ductus Deferens (sperm from epididymus) \n - Seminal Glands (release semen) \n - Prostate Glands (releases prostate fluid) \n - Urethra (fluid to exterior) \n - External Genitalia (Penis & Scrotum)

Functions of Reproductive: Male system

\- Produce sex cells and hormones \n - Thermal control \n - Enhance secondary sexual characteristics

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Components of Reproductive: Female system

\- Ovaries (produce oocytes and hormones) \n - Uterine tubes (deliver oocyte, fertilization) \n - Uterus (embryonic development) \n - Vagina (lubrication, sperm reception and birth canal) \n - Mammary Gland (feed new born; also part of integumentary system)

Functions of Reproductive: Female system

\- Produce sex cells and hormones \n - Support embryonic development \n - Provide nutrition for baby \n - Enhance secondary sexual characteristics

Components of Urinary system

\- Kidneys \n - Bladder \n - Ureters \n - Urethra

Functions of Urinary system

\- Eliminate excess water, salt and waste (kidney) \n - Regulate blood volume and pressure \n - Assists blood cell production (Kidney - EPO)

Erythropoeitin (EPO)

\- EPO is a glycoprotein hormone produced by interstitial fibroblasts in kidneys in response to falling levels of oxygen in the tissues \n - Signals erythropoiesis (BC production) in bone marrow \n - Increases activity of hemocytoblasts (RBC stem cells) causing more RBC production \n - Increases carrying capacity of oxygen

Components of Respiratory system

\- Nasal Cavity and Sinus (Filters warm humidified air) \n - Pharynx (conducts air to larynx) \n - Larynx - vocal cords (protects opening to trachea) \n - Trachea (filters air) \n - Bronchi (conducts air between trachea and lungs) \n - Lungs (site of gas exchange)

Functions of Respiratory system

\- Detects smell (nasal cavity) \n - Produces sound (larynx) \n - Gas exchange (lung) \n - Acid base control (lung)

Components of Endocrine system

\- Pineal Gland (circadian rhythm) \n - Pituitary Gland (other endocrine glands / controls growth / fluid balance) \n - Thyroid gland (metabolic rate/calcium levels) \n - Thymus - (lymphocyte maturation) \n - Adrenal Glands (water balance / tissue metabolism) \n - Kidneys (RBC production / blood pressure / calcium level) \n - Gonads (reproduction / sexual characteristics) \n - Pancreas (glucose level)

Gigantism and Acromegaly

\- GH released from anterior pituitary \n - GH targets liver \n - liver releases IGF-1 (insulin-like growth factor-1) \n - IGF-1 targets muscle, skin, bone, etc. \n \n Gigantism: too much GH from childhood \n Acromegaly: too much GH as an adult

Functions of Endocrine system

\- Directs long term change in other organs \n - Regulate body activity

Components of Digestive system

\- Oral Cavity (breaks up food) \n - Salivary Glands (buffers and lubricant) \n - Pharynx (transfer food to oesophagus) \n - Oesophagus (deliver food to stomach) \n - Stomach (secretes acids and enzymes) \n - Small Intestine (release digestive enzymes, absorbs nutrients) \n - Large Intestine (water removal, waste storage and removal) \n - Gall Bladder (concentrates bile) \n - Liver (secretes bile) \n - Pancreas (release digestive enzymes and relevant hormones)

Functions of Digestive system

\- Process food \n - Absorb food \n - Absorbs water \n - Eliminates solid waste

Organs in more than one system

\- Pancreas (D&E) \n - Mammary Gland (R&I) \n - Testes (R&E) \n - Ovaries (R&E) \n - Thymus (L&E) \n - Kidneys (U&E) \n - Pharynx (R&D)

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Types of epithelial tissues

1\. Covering and lining epithelia \n 2. Glandular epithelia

Covering and lining epithelia

\- Forms the outer coveringof skins and some internal organs \n - Forms the inner lining of blood vessels, ducts and body cavities, interior of respiratory, digestive, urinary and reproductive systems

Glandular epithelia

Constitute the secretory portion of the glands

General functions of epithelial tissues

\- Selective barriers to limit or aid transfer \n - Secretory function onto a free surface \n - Absorption of nutrients etc \n - Protection especially against abrasions

Types of cell junctions

\- Tight junction \n - Adherens junction \n - Gap junction \n - Desmosome \n - Hemidesmosome

Tight junction

\- Branching network of individual sealing strands mainly composed of claudins and occludins \n - Junction joins the cytoskeletons of adjacent cells (e.g. anchors actin to membrane proteins) \n - Electronically tight; prevents migration of proteins and passages of ions/molecules \n - Present closer to the apical side

Adherens junction

\- Junction in which protein catenins link transmembrane protein cadherins to actin in the cell cytoplasm \n - Role is to hold two cells together and maintains cell structure \n - More basal located than tight junction

Gap junction

\- 6 protein connexin form connexon (hemichannel), and creates a gap junction when two hemichannel of different membranes interact with one another \n - allows direct connection between cells \n - allows various molecules, ions and electrical impulses to directly pass to adjacent cells

Desmosome junction

\- Junction in which cadherins spans the gap, binding to keratin in the cell cytoplasmic intermediate filament (no catenins, but plaque) \n - Role is to resist shearing forces, thus present in places with high mechanical stress (e.g. muscle)

Hemidesmosome

\- Junction in which integrin spans the gap, binding to keratin in the cell cytoplasmic intermediate filament to \*laminin" in the basement mebrane \n - Connects epithelia to basement membrane \n - Present on the basal side of the epithelial cell

Microfilaments

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\- Type of cytoskeleton \n - Composed of mainly actin \n \n - Function is to: \n 1. Provide structural support and alters cell shape \n 2. Be used for muscle contraction \n 3. Provide strength \n 4. Link cytoplasm to membrane, cell to cell

Intermediate filaments

\- Type of cytoskeleton \n - Composed of various proteins, (e.g. keratin - Type 1/2) \n \n - Function is to: \n 1. Provide structural support \n 2. Move materials through cytoplasm \n 3. Resists mechanical stress

Microtubules

\- Type of cytoskeleton \n - Composed of subunits of tubulin \n \n - Function is to: \n 1. Act a scaffold to determine cell shape \n 2. Move materials through cytoplasm \n 3. Form the spindle fibers during mitosis \n 4. Be used for locomotion

Basement membrane

A membrane found between epithelial cells and connective tissue cells, composed of the basal lamina and reticular lamina

Function of basement membrane

1\. supports the overlying epithelium \n 2. provides a surface along which epithelial cells migrate during growth and wound healing \n 3. acts as a physical barrier

Basal lamina

Top half basement membrane layer secreted by the epithelial cells. It contains Collagen, Laminin, other proteoglycans and glycoproteins.

Reticular lamina

Bottom half basement membrane layer produced by fibroblasts (in the connective tissue). It contains fibrous proteins such as fibronectin, collagen

Nutrients and wastes exchange in epithelia tissues

Epithelial tissues contain nerves but are avascular \n \n Exchange of nutrients and wastes take place by diffusion from vessels in the connective tissue

Melanoma

\- Basement membrane can act as a barrier to invasion \n - One the BM has been penetrated, change of metastasis increases significantly \n \n ABCDs of melanoma: \n A - asymmetry \n B - border irregularity \n C - colour (mix of brown, black, red, white or blue) \n D - diameters (>6mm)

Classification of epithelial cells (arrangement)

1\. Simple = single layer (function = secretion, absorption, filtration) \n 2. Stratified = two or more layers (function = protective) \n 3. Pseudostratified = appears to be stratified as judged by position of nuclei, but actual are simple epithelium (function = secretion, protection)

Classification of epithelial cells (shape)

1\. Squamous = flat and thin (function = diffusion) \n 2. Cuboidal = cuboid (function = secretion, absorption) \n 3. Columnar = more tall than wide (function = secretion. absorption) \n 4. Transitional = stratified epithelium in which cells change shape from cuboidal to squamous (function = storage)

Simple squamous epithelium

\- Appearance: thin, flat, delicate \n \n - Sub-Types: \n A. Mesothelium - lines pericardial (heart), pleural (lung), peritoneal (gut) cavities \n B. Endothelium - lines inside heart + blood vessels \n \n - Features: filtration (kidney), diffusion (lungs), secretion (serous membrane) \n - Location: bowman capsule (kidney), alveoli (lungs), visceral cavity linings, blood vessels, heart

Simple cuboidal epithelium

\- Appearance: cuboidal or hexagonal boxes where distance between adjacent nuclei is approx the height of epithelium \n \n - Features: secretion (ducts), absorption \n - Location: ducts (pancreas, kidney duct), salivary glands, thyroid secretory chambers, lens surface, pigmented epithelium at posterior of retina, seminiferous tubules

Simple columnar epithelium

\- Appearance: rectangular, taller and more slender than cuboidal type; nuclei often elongated \n - More cytoplasm = more organelles = capable of higher level of secretion and absorption than are cuboidal cells \n \n - Sub-Types: \n A. Non-ciliated - has non-motile microvilli and goblet cells \n B. Ciliated - has motile cilia and goblet cells

Non-ciliated simple columnar epithelium

\- Appearance: columnar, has microvilli on apical surfaces, contain goblet cells \n \n - Features: secretion and lubrication (goblet cells), absorption (gut) \n - Location: gastrointestinal tract (stomach, small intestine); ducts of many glands; gallbladder

Microvilli

Non-motile cytoplasmic project that increases surface area for absorption

Ciliated simple columnar epithelium

\- Appearance: columnar, has cilia on apical surfaces, contain goblet cells \n \n - Features: secretion and movement of mucous by cilia towards throat, movement of oocytes expelled from ovaries through uterine (fallopian) tubes into uterus. \n - Location: bronchioles (respiratory tract), fallopian tubes, central canal of spinal cord, and ventricles of the brain.

Stratified squamous epithelium

\- Appearance: cells closer to the basal side is more columnar, gaining squamous properties as it reaches the apical side \n - located where mechanical or chemical (e.g. dehydration) stress is severe or is susceptible to microbes \n \n - Sub-Types: \n A. Keratinized - contains large amount of keratin in apical layers making surface tough and waterproof \n - as cell move to apical side, they move away from the blood supply and become dehydrated/less metabolically active, and cell becomes touch and hard and less metabolically active \n B. Non-keratinized - contains large amount of keratin in apical layers, and is continuously moistened by mucus \n \n - Features: protection (skin, mouth, throat, anus, vagina) \n - Location: skin (keratinized), mouth, throat, tongue, esophagus, anus, vagina (non-keratinized)

Stratified cuboidal epithelium

\- Appearance: cells in apical layer are cube shaped; fairly rare to see \n \n - Features: protection, limited secretion (ducts), absorption \n - Location: ducts of adult sweat glands, oesophagel glands, male urethra

Stratified columnar epithelium

\- Appearance: basis layer consist of shortened, irregularly shaped cells; only cells in apical layer are columnar shaped; rare to see \n \n - Features: protection, secretion \n - Location: pharynx lining, part of urethra, some large gland ducts such as in oesophageal glands, anal mucous membrane, part of conjunctiva of the eye

Stratified transitional epithelium

\- Appearance: (relaxed) looks like stratified cuboidal epithelium , except apical layer cells tend to be large and rounded. (stretched) cells become fl =atter, giving the appearance of stratified squamous epithelium \n - Multiple layers and elasticity make it ideal for lining hollow structures subject to expansion from within. \n \n - Features and location: storage of urine in bladder

Pseudostratified columnar epithelium

\- Appearance: all cell contact basement membrane but not all reach the apical surface of the tissue, nuclei at all different levels \n \n - Sub-Types: \n A. Non-ciliated - has no cilia or goblet cells \n B. Ciliated - has motile cilia on some cells, has goblet cells

Ciliated pseudostratified columnar epithelium

\- Appearance: columnar, has cilia on apical surfaces, contain goblet cells \n \n - Features: secretion and movement of mucous \n - Location: most of upper airways

Non-ciliated pseudostratified columnar epithelium

\- Appearance: columnar, has no goblet cells or cilia \n \n - Features: absorption and protection \n - Location: larger ducts of glands, epididymis, parts of male urethra

Glandular epithelia

Consist of a single cell or a group of cells that secrete substances\* into ducts (tubes), onto a surface, or into the blood in the absence of ducts. \n \n Either classified as endocrine or exocrine

Endocrine glands

\- These glands secrete hormones, which enter the interstitial fluid and then diffuse directly into the blood stream without flowing through a duct \n - They have far-reaching effects because they are distributed throughout the body by the bloodstream

Function of endocrine glands

Hormones regulate many metabolic and physiological activities to maintain homeostasis. \n \n e.g. pituitary gland at base of brain, pineal gland in brane, thyroid and parathyroid glands near larynx, adrenal glands superior to kidneys, pancreas near surface, ovaries in pelvic cavity, testes in scrotum, thymus in thoracic cavity.

Structure of endocrine glands - \####*Blood vessels*: in close proximity for immediate hormone release

Blood vessels: in close proximity for immediate hormone release \n Hormone producing cell: on the edge \n Stored precusor of hormone: in the centre \n \n No ducts present as hormone enters blood tranversing interstitial fluid

Exocrine glands

\- Glands that secrete their products into ducts that empty onto the surface of a covering and lining epithelium such as the skin surface or the lumen of a hollow organ. These glands can be classified as either unicellular or multicellular. \n \n Secretion of exocrine glands would be harmful if they enter the bloodstream

Function of exocrine glands

Produce substances such as sweat to help lower body temperature, oil, earwax, saliva, or digestive enzymes. \n \n e.g. sweat, oil, and earwax glans of skin; digestive glands such as salivary glands (secrete into mouth cavity) and pancreas (secretes into small intestine).

Basic structure of exocrine gland

Ducts: present in the centre so secretion could be collected in the lumen \n Secretory cells: on the inner edge of the duct \n \n No blood vessels in extreme proximity

Organ with both endocrine and endocrine gland

Pancreas has both exocrine secretory cells placed closer to the duct, while distance to it, endocrine secretory cells (pancreatic islet) are present

Classification of multicellular exocrine glands (ducts) - \####Structure of secretory area

Structure of secretory area \n A. Tubular - has tubular secretory parts. \n B. Acinar/alveolar - has rounded secretory parts \n C. Tubuloacinar - has both tubular and acinar parts \n \n Structure of duct \n 1. Simple - duct of the gland does not branch on the way to the gland cells \n 2. Branched - several secretory area share a duct (refers to the glandular area only) \n 3. Coiled - duct appear coiled \n 4. Compound - duct of the gland branchs on the way to the gland cells.

Single gland cell

In epithelia that have independent scattered gland cells, the individual secretory cells are called mucous cells that secrete mucin. The apical cytoplasm is filled with large secretory vesicle that contains mucin

Simple tubular glands)

Intestinal glands (large intestine)

Simple branched tubular glands

Gastric glands, mucous glands of esophagus, tongue and duodenum

Simple coiled tubular glands

Sweat glands

Simple acinar glands

A stage in the embryonic development of simple branched glands

Simple branched acinar glands

Sebaceous (oil) glands

Compound tubular glands

Mucous glands (mouth)

Bulbo-urethral glands (male reproductive system)

Seminiferous tubules of testes

Compound acinar glands -

Mammary glands

Compound tubuloacinar glands - ####

Salivary glands

Glands of respiratory passages

Pancreas

Functions of connective tissues

1\. Binds, supports and strengthens other body tissues \n 2. Transport system of the body (blood) \n 3. Stores energy reserves (fat or adipose tissue)

Features of connective tissues

\- not found on body surfaces \n - can be highly vascular (exception: cartilage) \n - supplied by nerves (like epithelia)

Connective tissue composition

Extracellular matrix (ECM)

Composed of: \n - ground substance (GS) \n - 3 types of protein fibres secreted by the cells in ECM

Relationship between ECM and connective tissue quality

Composition/character of ECM dictates the connective tissue qualities \n \n e.g. cartilage - firm, rubbery ECM, bone - hard, inflexible ECM

Ground substance (GS)

Composed of: \n - Water \n - Proteins \n - Polysaccharides

Glycosaminoglycans (GAGs)

\- Long, unbranched polysaccharides \n - Highly polar so attracts water and make GS gel like \n - Repeating disaccharide unit of amino sugar (e.g. N acetylglucosamine) and uronic sugar (e.g. glucuronic acid) \n \n Also known as mucopolysaccharides

Proteoglycans

Protein compound made up of core protein and glycosaminoglycans (GAGS) \n Subclass of glycoprotein

Sulphated glycosaminoglycans (GAGs)

Type of sulfate-containing glycosaminoglycans that bind to protein backbones to form proteoglycans \n \n Dermatan sulphate \n Heparin sulphate \n Keratan sulphate \n Chondroitin sulphate

Non-sulphated glycosaminoglycans (GAGs)

Glycosaminoglycan (Hyaluronic acid) with no sulfate containing group that is not covalently bound directly to protein but is joined by various proteoglycans

Hyaluronic acid

GAG that is viscous and slippery \n \n Roles: \n - binds cells together \n - lubricates joints \n - maintains shape of eyeball