Anatomy

Cell

Structure of the plasmalemma

  • Composed of lipids and two types of proteins 

  • Lipid bilayer with a hydrophobic inner layer between 

  • Integral or transmembrane proteins: proteins embedded or passing through the plasma membrane

  • Peripheral membrane proteins: associated with membrane but not embedded

  • On extracellular surface has CHO’s that attach to proteins (glycoproteins) or lipids (glycolipids) that form a cell coat (glycalyx)

  • Increase surface/space

  • Lipids rafts within membrane (cholestoral)


Movement across the plasmalemma (plasma membrane)

Large 

Endocytosis: substance enters cell 

  • phagocytosis : cell eating Ex: white blood cell engulfing bacteria 

  • Pinocytosis: cell drinking Ex: formation of small vesicles in capillary wall to move substances

  • Receptor mediated endocytosis: requires specific proteins EX: uptake of cholesterol into cells, mediated by a drug


Exocytosis: substance leaves cell 


Simple diffusion: some ions and small nonpolar substances can cross via this 

Small 

Diffusion (passive)

  • High to low

Osmosis 

  • Water molecules passive

Channels 

  • Open and close for passage of Na+, Ca++, K+ (high to low)

Protein carriers

Pumps use energy from ATP (going against concentration gradient)

Cell organelles and their functions

  • Mitochondria 

  • Mobile power generators, ATP

  • Present in all cells EXCEPT red blood cells and terminal keratinocytes (dead cells)

  • Inner membrane known as cristae (creates surface area)

  • More in cells that need energy 

  • Enzymes on inner membrane generate ATP

  • Endoplasmic reticulum and ribosomes

  • Involves rough ER ( network of channels) and ribosomes 

  • Ribosomes assemble polypeptides

  • Rough ER makes proteins 

  • Smooth ER synthesizes lipids

  • Proteins transported to golgi apparatus for modification and packaging

  • Ribosomes 

  • Free polyribosomes either go to proteins of cytosol & cytoskeleton, or to specific proteins imported to other areas, or to if they are disfunctional, they conjugate to ubiquitin 

  • ER-Bound Polyribosomes go to golgi apparatus and sorting or also conjugate to ubiquitin

  • Endoplasmic reticulum associated protein degradation (ERAD) targets bad/poor protein and sends it out to cytoplasm where ubiquitin attaches to it. 

  • Endoplasmic reticulum 

  • transports : moves molecules through cisternal space from one part to another 

  • Detoxification: smooth ER detoxifies both drugs and alcohol

  • Golgi apparatus

  • Modifies and completes protein synthesis initiated by rough ER 

  • Places protein in shipping vacoules to move within cell or be secreted

  • Cell granules

  • Secretory granules: push out sweat/liquids

  • Lysosomes: eat

  • Peroxisomes: oxidize substrates (sends oxygen)

  • proteasomes : associate with ERAD

Cytoskeleton structures / functions

Functions

  • Determine shape of cells

  • Movement of organelles

  • Movement of the cell 

  • Components: microtubles (largest), intermediate filaments (middle), microfilaments (smallest) 

  • microtubles

  • From near the nucleus and grow toward the cell periphery. CONNECTION WITH CELL

  • Guide vesicles in movement within cell 

  • Movement within cytoplasm 

  • Components: microtubles (largest), intermediate filaments (middle), microfilaments (smallest) 

  • microfilament

  • Actin filaments

  • In all cell types

  • Grouped in bundles

  • Functions 

  • Anchorage and movement of membrane proteins

  • Form structural core of microvilli

  • Extension of cell processes

  • Movement of cell/proteins

  • Intermediate filaments

  • Have a support and structural role 

  • Need to know classes

  • Keratin (epithelial cells)

  • Vimentin (mesoderm-derived cells like muscle, glial. Glial is part of the placenta) 

Structure of the nucleus of a cell

  • Membrane-limited compartment containing genes 

  • contains

  • Nuclear envelope: bilayer with perinuclear space between them and nuclear pores which regulate transport between and cytoplasm

  • Chromatin: chromosomal material

  • Nucleolus: site of active rRNA synthesis which then leads to protein synthesis

  • Nucleoplasm: material within nucleus that is not chromatin or nucleolus 


What are “stem” cells?

Progenitor cells or “tranist amplifying cells” whose cycling serves to renew the differentiated cells of tissues as needed


Epithelium

Identify the functions of epithelia

Principal function of epithelial tissues

  • Covering, lining, and protecting surfaces (eg, epidermis)

  • Absorption (eg, the intestinal lining)

  • Secretion (eg, parenchymal cells of glands. Secrete in kidneys to get rid of waste)

  • Transportation, excretion, sensory reception, and reproduction

  • AVASCULAR

Define the two types of epithelia

Covering- protects body inside and out

Glandular - facilitate secretions. 

Know the cell to cell junctions we studied on the basal and lateral surfaces of epithelial cells.

  • Tight junction (occluding junction) door: seals cells together to prevent molecules from leaking between them. 

  • Adherens junction lock: anchoring junctions 

  • Desmosome bolt- strong spot links between cells

  • Hemidesmosomes bolt- join epithelial cells to basal lamina, involve integrins

  • Gap junctions peep holes- small diffusion channels. Allow signaling

Define the basal lamina and its collagen

  • Composed of type IV (4) collagen, glycoproteins (laminin and enactin), and proteoglycans secreted by the epithelial cells

  • Laminin binds to type 4 collagen and integrins (hemidesmosomes)


Describe the types of free surface specializations of an epithelial cell

  • Cilia: move mucus & and other substances

  • Found in trachea, bronchi, oviduct

  • Larger than microvilli and contain microtubles 

  • microvilli : increase surface area for absorption 

  • Brush border of kidney tuble cell and small intestines

  • Striated border of intestinal absportive cell

  • stereocillia

  • Hair cells in ear

  • Long microvilli -> increases surface area

  • Think of stereo ( sound system)

What is the terminal web?

a network of actin filaments located just beneath the surface of the cell, anchoring the microvilli. It helps maintain the cell's shape and supports the structure of the microvilli, which are involved in absorption and secretion functions.

Describe the different types of covering epithelia and their functions

Simple

  • Flat, one layer

  • Simple squamous: allow active and passive movement of substances through tissue (gases, fluids, i.e. lungs)

  • Simple cuboidal: secretions (e.g  sweat or tears), absorption (water)

  • Simple columnar: protective, secretion and absorption. 

  • Types: ciliated (moves mucus) and non-ciliated (goblet cells secrete mucus and absorptive cells have microvilli)

  • Special names

  • Endothelium : internal lying of heart and blood vessels)

  • Mesotheloim (internal lining of ventral body cavities) 

Stratified

  • Multiple layers, can be keratinzed (dry, like skin) or nonkeratinized (wet, like gums)

  • Stratified squamous: superficial (TOP)  layers are flat. Deeper layers more cuboidal, deepest have continuous cell division 

pseudostratified

  • cells aren’t lined up perfectly so it looks like multiple layers but it's only ONE LAYER. IN

RESPIRATORY TRACT.  

  • All cells attached to basement membrane

  • Somse cells do not reach the free surface. 

  • Secrete or ciliated

Transitional 

  • Special stratified that lines pelvis of kidney, ureters, urinary bladder, and part of uretha 

  • Cells change shape according to the degree of distenison of the organ

  • ONLY IN URINARY TRACT

Differences between exocrine and endocrine glands

Endocrine glands- secrete HOROMONES into bloodstream 

Exocrine glands- secrete liquids juices into tubes or DUCTS that lead to the outside of the body (eg, sweat, saliva, mucus, stomach acid)

Types of exocrine glands

Unicellular

  • Goblet cells: secrete mucus

  • Found in CI and respiratory systems 

  • Scattered cells within epithelium 

Multicellular 

  • Secretory sheet 

  • Tubular invainatin 

  • Classification of tubular glands by structure 

  • Duct 

  • Simple: ducts DON NOT BRANCH

  • Compound (branching) ducts BRANCH INTO MORE AND MORE

  • Secretary part of gland 

  • Tubular (shaped like a tube, cylinder shape)

  • Acinar or alveolar (shaped like a blind sac, rounded)

  • Tubolacinar (longer rounded shape)

Some cells we have studied can change phenotype. What happens to them?

Connective Tissue

General features, components and functions of connective tissue

  • Connects tissues together 

  • NO FREE SURFACE (mixed in body) 

  • Has nerve supply

  • Highly vascular 

  • All CT develop from embryonic CT called mesenchyme 

Components

  • Specialized cells 

  • Extracellular matrix (greatest volume of CT)

  • Protein fibers

  • Collagen 

  • Elastic 

  • Reticular 

  • Ground substance 

Functions

  • Support, surround, connects other tissues

  • Forms structural framework of body 

  • Defends from invasion by microorganisms 

  • Stores energy reserves

  • Protects delicate organs 

  • Transports fluids and dissolved rom one region to another 

-blast, -cyte, -clast terminology

  • Blast: cells produce matrix

  • Cyte: cells maintain matrix

  • Clast: cells break down matrix

  • Example : osteoblast, osteocyte, osteoclast


Major cell types in CT and what do they do

Fixed- stable, make it their home, long lived 

  • fibroblasts/fibrocytes

  • Principal cell of CT

  • Produce collagen and elastin and ground substance

  • Target growth factors

  • Myrofibroblasts help close wounds. 

  •  macrophages

  • Comes from cells originating in bone marrow called monocytes

  • Can be fixed or wandering 

  • Irregular shape, cell surface uneven

  • Large size

  • Active in phagocytosis

  • Large amouns of golgi-apparatus, mitochondria, ER, secretory vesicles

  • Large lysosomes

  • Antigen-presenting cells (will take foreign object in cell and digest it)

  • Mast cells

  • Large, ovoid cell, wandering 

  • Small nucleus centrally located 

  • Secrete chemicals into surrounding environment 

  • Store chemcials which mediate inflammatory process i.e heparin, histamine, leukotrienes

  • Dependent on plasma cells to produce antibodies 

Transient- free, short-lived

  • Part of the immune system 

  • Leukocytes (White blood cells)

  • functions concerned with inflammation, invasion by foreign elements and immune response 

  • Circulate bloodstream 

  • Lymphocytes

  • Neutrophils

  • Eosinphils

  • Basophils

  • monocytes

  • Plasma cells

  • antibody - producing cells derived from B lymphocytes

  • Short life span (10-30 days)

  • Large, ovoid

  • Prominent golgi 

  • Round eccentric nucleus 

  • Found in lamina propria of gastrointestinal tract as well as respiratory tract, and salivary gland

EXAM QUESTION

Distinguish between diapedesis (wandering cells) and chemotaxis (chemical trail WBC follow to get to target cell)

Describe extracellular matrix


What are the three types of connective tissue fibers and any unique characteristics they may have

Collagen (like rope, provide strength in holding tissue together i.e the roll of the thread) 

  • Flexible, high tensile strength 

  • Multiple types

  • Type 1 most common 

  • Criss cross collagen = increasing strength

Reticular 

  • Extremely thin, arranged in network or mesh

  • Need silver stain to see

  • Fine fiber

  • Type 3 collagen

Elastic fibers

  • Thin and straight fibers

  • Type 1 collagen

  • Elasticity ages as one gets older 

  • If something goes wrong with elastic fibers, another mutation can occur 

Ground substance components and examples of them we gave in class

Surround cells and fibers of CT, unstructured

  • GAGs 

  • Most common 

  • Major building block of CT

  • Long chain of Amino Acids (disaccharide)

  • Sometimes attach to other molecules ( protein molecule to make a more complex molecule)

  • Ex: chondroitin sulfate (collagen), keratin sulfate (mkaing strength in skin) & hyaluronan (binds lots of things together . 

  • Proteoglycans (PG)

  • Aggrecan in cartilage

  • Syndecan in epithelial cells 

  • Glycoproteins  

  • Integrins are glycoproteins that bind cells and extracellular matrix

  • Role of extraceullular matrix is guiding stem cell fate

  • Multiadhesive glycoproteins

  • Integrins can interact with proteins within the cell

  • Fibronectin (most important adhesive matrix)

Describe the different types of connective tissues and examples of tissues with them. Be able to compare 

and contrast them.

Connective tissue proper 

  • Loose (areolar) CT

  • Comprised all main components of CT proper 

  • Fibroblasts and macrophages most numerous

  • Flexible, very vascular, not resistant to stress

  • Not strong 

  • Not alot of collagen 

  • Dense 

  • Irregular

  • Cells are primarily fibroblasts

  • Most tissue consists of collagen fibers

  • Type 1 collagen

  • Very strong

  • Collagen fibers in bundles, run in different directions and it makes it very strong 

  • Types: dermis, sheaths and capsules

  • In joints

  • Underneath skin 

  • Regular 

  • Cells are primarily fibroblasts 

  • Collagen arranged in bundles with definite orientations. Not as strong as irregular 

  • types:

  • tendon/ aponeuronsis (flat tendon)

  • Ligaments (join bones together)

  • Elastic tissues

Connection tissue with special properties 

  • Embryonic 

  • Mesenchyme 

  • Gives rise to almost all CT

  • Mucous connective tissue (jelly like)

  • Primary in umbilical cord

  • Whartons jelly

  • Pulp in young teeth 

  • Reticular 

  • Forms the delicate stroma of the pymphoid organs and soft organs 

  • Within the bone itself. Give rise to future bones

  • Around blood vessels 

  • Binds smooth muscle cells together 

  • Fine matrix of branched reticular fibers produced by reticular cells, specialized fibroblasts

  • Adipose

  • Fluid (hematopeietic) connective tissue 

Adipose

Adipose tissue is a connective tissue


Types of adipocytes

White = unilocular - one droplet

  • Energy storage sit 

  • Pushes nucleus and cytoplasm against mitochondria 

  • Synthesize and store triglycerides 

Brown= multilocular- multiple droplets

Functions of adipocytes

Short term

  • Controls appetite and metabolism 

  • Ghrelin appetite stimulate ( tells body to eat)

  • Peptide YY (tells body stop/not eat)

Long term

  • Leptin : tells brain you have enough fat

  • Insulin - pushes glucose out of bloodstream into cell

Mobilization and storage of triglyceride

  • Stored in white adipose 

  • Mobilized through autonomic nervous systems and hormones. 

Characteristics of White Adipose

  • Energy storage sit 

  • Pushes nucleus and cytoplasm against mitochondria 

  • Synthesize and store triglycerides 

Characteristics of Brown Adipose

  • Smaller, store more droplets of fat

  • Nucleus stays in place

  • For heat production 

  • Numerous mitochondria (since it makes heat)

Cartilage

Structure and characteristics of cartilage

  • Cartilage consist of chondroblasts

  • Avascular, lacks nerves and lymphatic vessels 

  • Three types: hyalie, elastic, fibrocartilage

  • Surrounded by sheath of dense connective tissue PERICHONDRIUM

How does cartilage develop?

  • Formed from chondrogensis with mesenchyme (embryo)

Types of cartilage, their characteristics, where do you find them

Hyaline

  • Type 2 collagen 

  • Ex: joints, ankles, knees, bronchi, larynx, nose

  • LINE THINGS

  • Aggrecan interacts with collagen, chondronectin binds cells to ECM

  • Chondrocytes reside in lacunae (cell nest)

  • Grows apppositional and interstitial

  • Calcifies before replaced

Elastic

  • Hold things together and shock control 

  • Matrix contains elastin 

  • Located in external ear, ear lobe, epiglottis (vocal cords)

  • Expand and contract with elastic fibers

  • Surrounded by perichondrium 

  • Type 1 collagen 

fibrocartilage

  • Fewer chondrocytes than other cartilage

  • MIX between elastic and hyaline

  • Type 1 and 2 collagens 

  • In areas of high stress such as intervertebral dics, mandibular condyle, symphysis pubis, menisci of knee

  • No perichondrium 

Function of each type of cartilage

Hyaline

  • Bone development and growth 

  • Facilitates the lengthening of long bones

Elastic 

  • Expand and contract with elastic fibers

Fibrocartilage 

  • Acts more as shock absorber

  • Holding things together and shock control 

Hyaline cartilage formation and repair

  • Growth occurs by interstitial (grow up and down) and appostitional (side growth)

  • Repair is limited.

  • Calcifies (hardens) before replacing. 

Structure of the epiphyseal growth plate

  • Cartilage disc that allows bones to grow in length and width in children and teens

Describe the perichondrium

  • Composed of two layers : inner cellular layer and outer layer

  • Inner cellular layer is source of cartilage cells 

  • Outer contains fibroblasts which produces collagenuous fibers and blood vessels. 

  • Found around the perimter of elastic cartilage and hyaline cartilage

Structure of bone


Bone

Describe bone matrix

  • Both collagen and ground substance are minrealized (calcified, which means to harden)

  • Composed of type 1 collagen (strongest, biggestm toughest)

  • Major mineral: calcium phosphate in form of hydroxyapatite crystals 

Compare and contrast bone and cartilage

Bone 

  • Bone is type 1 collagen

  • Have perichondrium/periosteum of two layers

  • Conatains osteocytes and is characterized by a mineralized extracellular matrix 

  • Osteocytes reside is lacunae in bone 

  • Osteocytes are in direct contact with each other (always communicating)

Cartilage 

  • Cartilage is type 2 collagen

  • Cartialge conrains chondrocytes (are alone, not communicating) and specialized extracellular matrix 

  • Have perichondrium/periosteum of two layers

Types of bone cells and their functions

Osteoblasts

  • Bone formation 

  • 2nd biggest

  • Active in protein synthesis 

  • Secretes type 1 collagen and osteoid (initial unmineralized matrix)

  • Promite calcification by alkaline phosphatase secretio 

  • Cuboidal in shape 

Osteocytes

  •  maintaining boney matrix

  • Most bone is osteocyte

  • Originate from osteoblasts

  • Occupy in lacunae in mineralized matrix

  • Contain extensive cellular dendritic processes which travel through boen in canniculi (allows bone to remodel)

  • Secrete growth factors which activate lining cells or stimulate osteoblasts or osteoclasts

  • Long-term viability 

  • Bone is always changing 

Osteoclasts

  • Bone resportion 

  • Small portion of bone is osteoblasts

  • Multinucelated giant cells found in contact with the bone surface 

  • Function to resolve bone:

  • Enhance Ca2+ re;ease from the bone as needed for Calcium homeostasis

  • Break down old or damaged bone allowing for new bone formation 

  • Reside in depression called resportion bays ( howship lacunae) 

  • When active produce ruffled border 

  • Originate from bone marrow 

  • They come from macrophages

Types of bone, woven vs. lamellar bone

  • Primary or woven (immature)

  • First to apper in development

  • First to appear in fracture repair 

  • Collagen fiber not organized, less mineralized

  • We see it when a bone breaks

  • Secondary or lamellar (mature)

  • Replaces primary bone

  • Organized

  • Osteon- concentric lamellae

  • Perforating canals connect blood vessels in central canals of osteons with periosteum


What is an osteon

  • Concentric lamellae

  • Basic functional unit of the compact bone 

Endochondral vs intramembranous ossification

Endocondral

  • Mesenchym cells (CT) condenses to form cartilaginous “bone” models which will be replaced by ossified tissue

  • (bones in arms and legs)

  • Cartilage formed into bone

  • Interstitial growth 

Intramembranous 

  • Bone forms directly from condensed mesenchyme cells which differentiate directly into osteoblasts. Most flat bones are formed this way. 

  • Most flat bone (like skull)

  • Mesochyme cells straight to bone 

Appositional vs interstitial growth

  • Interstitial growth is within 

  • Appositional is width on the outside growing. 

Hormonal regulation of blood calcium levels

  • Skeleton acts as calcium reservoir 

  • Calcium in blood and tissues is stable due to interchange of blood and bone calcium 

  • When therer are more holes in bone then it turns into osteoporosis. It takes too much calcium