Bio 2 Test 3

Glycogen

Storage carb

Types of tissue

1. Epithelial

2. Connective

3. Muscle

4. Nervous

Epithelial Tissue

Specialized to protect and to secrete/absorb ions and organic molecules

Epithelial cell shapes

cuboidal, squamous, and columnar

epithelial cell layers

1. simple - 1 layer

2. stratified - multiple layers

3. pseudostratified - 1 layer appears stratified

All Epithelial tissues

are asymmetrical or polarized (one side rests on basement membrane and the other faces environment.

Types of Epithelial Tissue

• Simple squamous, Stratified squamous (skin)

• Simple cuboidal

• Simple columnar, Pseudostratified columnar

• Transitional - stretchable

Connective tissues form

extracellular matrix around cells

Types of connective tissue

• Blood - transport & protection

• Adipose - (fat) insulation, energy, support & protection

• Bone - support & protection

• Cartilage - support & flexibility

• Loose - holds internal organs in place

• Dense - strength and support

Nervous tissue is a

complex networks of neurons

Neuroglial cells

more numerous than neurons

Provide metabolic support, maintenance, ion balancing and cleaning for the neurons

Produce new glial cells & neurons

Organs

2 or more kinds of tissue

Integument functions

Protect from abrasion, water loss, uv light

Barrier to disease causing pathogens

Temp regulation

Sensory/touch

Excretion (limited) - evaporative cooling

Epidermis

Stratified Squamous Epithelium

Epidermis cell types

• Langerhans Cells - Defense

• Melanocytes - Melanin, protect uv light

• Merkel Cells - touch receptors

• Keratinocytes - primary cell type, keratin (increases from inside to outside) (keratin fills cytoplasm and impairs nutrient diffusion thus cells die)

Dermis

Highly vascularized

Contains sensory structures, vessels, nerves, glands

Origin of hair, feathers, scales

Dermis sensory structures

Meissner’s Corpuscles - light touch

Pacinian corpuscles - deep pressure, vibration

Sweat Gland

2.5 mil in body

Sebaceous Glands

All over body except palms & soles

Large on face, neck, & upper chest

Produce sebum - lubricates and softens hair and skin

Hypodermis (subcutaneous layer)

beneath dermis - NOT a layer of skin

lots of adipose tissue

Function: body contour, insulation

Females thicker layer

Gut Tract types (2)

1. Blind Gut

   • no cavity btwn gut and body wall

   • 1 opening

   • primitive form

2. Tube-within-a-tube

   1. flow through digestive tube

   2. body cavity btwn gut and body wall

   3. separate openings (mostly)

   4. advanced

Digestive Enzymes (hydrolases) (require H₂O

1. Carbohydrases

2. Proteases

3. Lipases

4. Nucleases

Food Processing Step 1/5

Ingestion - food is taken into the body and moves into a digestive cavity/tube/tract (usually the alimentary canal)

Food Processing Step 2/5

Digestion - food is broken down into smaller molecules

Chemical & mechanical digestion

Food Processing Step 3/5

Transport

Food Processing Step 4/5

Absorption - ions, water, and small molecules diffuse or are transported into the circulatory system

nutrients, vitamins, hormones

Food Processing Step 5/5

Egestion/Elimination/Excretion - undigested materials and other wastes are passed from the body

Alimentary Canal

digestive tract or tube (GI tract) - single elongated tube w an opening at both ends

smooth muscle in walls

lined by epithelial cells

several specialized regions

Structure of GI tract

• Same structure from midpoint of esophagus to anus

  • Lumen lined by epithelial and glandular cells

  • Secretory cells release layer of mucus

  • Other cells release hormones

  • Glands release acid, enzymes, water, and ions

• Epithelial cells linked by tight junctions and surrounded by layers of tissue made of smooth muscles, neurons, connective tissue, and blood vessels

  • Neurons activated by sight and smell of food, presence of food in tract

Region of Reception

• Buccal cavity (mouth and accessory structures)

• Ingestion site and Digestion site (chem & mechanical)

• Jaws, teeth, cheek muscles, tongue, salivary glands (saliva - enzyme Amylase)

• Pharynx - back of mouth cavity

  • point that digestive & respiratory system cross paths

Region of Conduction

• Esophagus - tube carrying materials from mouth cavity to rest of the alimentary canal (neck region through chest)

• Conducts food from pharynx to stomach

• Peristalsis: rhythmic, wave-lake contractions which propel food foreword in GI tract

Region of Storage and More Digestion

• Stomach (mostly

• Saclike organ evolved for storing food

  • muscular nature helps break up food; partial protein digestion

  • Regulates rate of emptying into small intestine

• Secretions

  • Hydrochloric acid - kills microbes, dissolves particulate matter (parietal cells)

  • Pepsinogen - converted to pepsin to begin protein digestion (chief cells)

• Epithelium coated w alkaline mucus

• Lumen (cavity) stomach:

  • pepsinogen + HCl → Pepsin (protein breakdown)

Region of Terminal Digestion & Absorption

• Small Intestine

  • Nearly all digestion of food and absorption of food

  • Hydrolytic enzymes found on apical surface of epithelial cells or secreted by pancreas into lumen

  • Products of digestion absorbed across epithelial cells and enter blood

    • vitamins, minerals, and water also absorbed

Surface area specializations

• Small intestine specialized to carry out the bulk of digestion and absorption

  • Mucosal infoldings

  • Villi - finger like projections

    • epithelial cells w microvilli create brush border (extensions of plasma membrane)

• Specializations increase area 600-fold

  • increases likelihood of food particle encountering digestive enzyme and being absorbed

3 regions of small intestine

• Duodenum - lots of secretions into this region

• Jejunum

• Ileum

Surface modifications that increase surface area for absorption (3)

1. Plicae circulares:

   • Large folds of the epithelial lining

   • Increase the surface are 2-3 times

2. Villus (Villi)

   • Finger like projections

   • Increase surface area 10 times

3. Microvilli

   • Folding of the plasma membrane of cells lining the villus

   • Increase surface area 20 times

Region of H₂O Absorption/Concentration of Solids

• Large Intestine

  • Mammals - about 1.5 meters

  • Lack plicae, villi, microvilli

  • H₂O absorbed through epithelium

  • Function - humans (about 1,400 ml/day H₂O

  • Compacts and elimination of feces

Waste

• Water 75%

• Inorganic substances 5%

• Roughage 8%

• Fat 5%

• Undigested protein, dead cells, bile 2%

• Limited vitamin synthesis by resident bacteria

Anus/Cloaca

• Anus

  • opening at posterior end of alimentary canal for the release of waste material

• Cloaca (some vertebraes)

  • chamber receiving contents of digestive, reproductive and urinary tracts; vent opening to the outside

Accessory Digestive Glands

NOT part of the Alimentary Canal

• Pancreas - secrete enzymatic juices through the pancreatic duct into the duodenum of the small intestine

• Liver - produces bile (assists enzymes in break down of large fat globules into smaller forms)

• Gall Bladder - storage of bile

Biomolecule

• Carbohydrates: polysaccharides → mono & disaccharides

  _ starch or glycogen fructose, glucose, sucrose

• Proteins: polypeptides → amino acids

• Fats: glycerol & fatty acids

• Nucleic acids: nucleotides (individual subunits of nucleic acids)

  • Enzyme activity for chem rxns at biological temps

Nervous system

Central nervous system (CNS) - brain and nerve cord

Peripheral nervous system (PNS) - all neurons and their projections that are outside of the CNS

In certain invertebrates w a simple nervous system, the distinction is less clear/not present

Cellular Components of Nervous Systems

• Nervous system have 2 classes of cells:

  1. Neurons (nerve cells)

  2. Glia (neural glial cells)

Parts of Axon

Axon hillock - near cell body

Axon terminals - tips

Glia

1,000 x more numerous than neurons

1. Astrocytes

   1. metabolic support and maintain stable [ ] of ions in extracellular fluid

2. Microglia

   1. immune functions and remove cellular debris

3. Oligodendrocytes

   1. produce nodes of Ranvier

4. Schwann cells

   1. nodes of Ranvier

5. Radial Glial Cells

3 types of neurons

1. Sensory

   1. transmit to CNS

2. Motor

   1. transmit away from CNS

3. Interneurons

   1. interconnections btwn other neurons

Resting Membrane Potential

inside (-), outside (+)

Nerve Impulse - Resting Potential

• imbalance btwn K+ and Na+ inside/outside

  • membrande selectively permeable to K, but channels closed for Na and Cl

  • outside neuron - 10x more Na, 5x more Cl

  • Inside neuron - 30x more K

Nerve Impulse - Action potental

• rapid/breif change of a nerve fiber

  • channels for Na open and Na diffuses in

  • K is already diffusing out, but increases at impulse

  • after a point membrane returns to resting

Nerve Impulse - Sodium/Potassium Pump

• pump out Na and carry in K

• returns the imbalance/normalicy

Nerve Impulse rate

Invertebrate - speed related to Axon diameter

Vertebrate - speed related to Axon diameter and myelin sheath

Phylum Cnidaria

simplest neural organization

nerve net - just primitive cells

Phylum Platyhelminthes

2 anterior ganglia, each w network branching off

weak PNS and CNS ( no brain or spinal cord)

Phylum Annelida

brain, ventral nerve cord, simpler motor/sensory neurons

Phylum Mollusca

complex

Phylum Arthropoda

slightly better

social insects - well dev brain, complex social behaviors, learning, division of labor, comm

Meninges layers - surround CNS

1. dura mater (outer)

2. arachnoid (middle)

3. pia mater (inner)

Brain

increase in size w complexity and vetebrae evolutions

3 divistions

1. hindbrain

2. midbrain

3. forebrain

Brain:spinal cord ratio

Fish 2:1

Amphibians 10:1

Reptiles 25:1

Birds 35:1

Humans 55:1

Hydroskeletons

found in some soft-bodied invertebrates that use water pressure for propulsion

Bone

composed of collagen - triple helix

crystaline mix of Ca2+, Po4- and other ions

Formation -

1. endochondral - bone replacing cartilage

2. intramembranous - bone forms w/in tissue membranes

1 cubic inch sustains 19,000 lbs

1mm diameter fiber of collagen can hold 19 lbs of dangling weight

Types of bone tissue

1. compact - composed of osteons

2. spongy - consist of bony spikes

Microscopy Anatomy of Compact Bone

Osteon

Osteonic canal - support and protection from damage, space for arteriole, venules, and nerves

Trabeculae ( spikes of spongy bone)

Periosteum - protective layer ouside of bone

Lamellae - ring of bone tussue as it dev

Lacuna - space btwn each lamella where osteocytes are located

canaliculi - microscopic channels connecting lacumae

Yellow and Red bone marrow

1. Yellow bone marrow - Diaphysis

2. Red bone marrow - Epiphysis

Muscle types

1. caridac - branched, multinucleated, striataed

2. smooth - 1 nucleus per cell

3. skeletal - multinucleatdd, striated, voluntary