~L1-4: Transport, Tissues, Integument

Water is an important substance in the body because:

• It can act as a _________ and __________

• Provides ___________

• Has high _________ and __________

• reactant - solvent

• lubrication

• surface tension - heat capacity

The categories of biological organic molecules:

• Lipids

• Amino Acids

• Carbohydrates

• Nucleotides

A cell is produced from ________ and specializes for a specific function through ____________.

cell division - differentiation

The cell cycle goes between cell _________ and the cell __________

division - performing it’s physiological function

The cell cycle is regulated by _______ and spends most of the time in __________

genes - interphase (not dividing)

When cell cycle regulation is disrupted, _________ can occur leading to ______ which then can turn into __________

abnormal cell division - tumors - cancer

Metastasis:

tumor cells break into surrounding tissue, developing a cancer, e.g. epidermis → dermis

Cytoplasm = __________ + ___________

cytosol - organelles

______ is intracellular fluid

cytosol

ICF has higher _______ and _______ concentrations

K+ - Large Anions

ECF has higher __________ and ____________ concentrations

Na+ - Cl-

Movement across the membrane through membrane proteins:

Facilitated Diffusion/Transport

What can cross the membrane through facilitated transport? (3)

• Water

• Water-soluble molecules

• ions

Free diffusion:

Molecules cross the membrane with no protein assistance

What can cross the membrane through free diffusion? (3)

• Lipids

• Lipid-soluble molecules

• Soluble gases (O2 + CO2)

Molecules that are too large even for __________, can only be transported by _____________

membrane channels - carrier mechanisms

An example of transport that requires ATP:

Vesicular Transport

Passive transport: substances move according to

according to their concentration and electrochemical gradients

Primary active transport:

Pump protein directly uses ATP

Secondary active transport:

Uses a gradient of one molecule made with ATP to move another molecule.

Water diffuses across a selectively permeable membrane according to __________

osmotic gradients

Hypertonic: solute concentration is higher _______ the cell, the cell ______

outside - shrinks

Hypotonic: solute concentration is higher _______ the cell, the cell ______

inside - expands

Homeostasis requires three components:

• Sensor

• Integrator

• Effector

Allostasis:

The body changes baseline’s to accommodate different conditions

Cells differentiate by expressing different ________ of ________.

combinations of proteins

Four general types of tissue:

1. Epithelial

2. connective

3. Muscle

4. Nervous

Tissue = ________ + _____________

cells + extracellular material

Muscle tissue function:

contracts to produce mechanical force

Nervous tissue function:

send and receive information in the form of electrochemical signals

Epithelial tissue lines _______ and ________ surfaces, __________, and _________.

internal and external - glands - passageways

Epithelial tissue provides ________ and _______, controls __________, and produces __________.

protection and sensation - permeability - secretions

Epithelium:

sheet of epithelial cells attached to a basement membrane.

All epithelial cells have a ______ surface (contact with lumen) and a ________ surface (in contact with ISF)

apical - basolateral

Paracellular transport: passive movement of molecules and ions ______ the ______ of an epithelial or endothelial cell layer.

between - cells

There are two types of tight junctions:

• _________: allow __________ transport of molecules

• _________: allow __________ transport of molecules

Leaky: paracellular

Tight: transcellular

Epithelia can be ________ or ________ and be ___________, ___________, or ___________ shaped.

• simple - stratified

• squamous - cuboidal - columnar

• ________ shaped cells have an apical surface wider than lateral surface.

• ________ shaped cells have an apical surface narrower than lateral surface.

• Squamous

• Columnar

Connective tissue ________ and __________spaces in the body

fills - stiffens

Connective tissue = _____________ + ______________

extracellular protein fibres + cells suspended within a matrix

Connective tissue’s function is to provide _________ for the body and other tissues, store _______ in the form of _________, protect the body from ____________

support/framework - energy - triglycerides - invading microorganisms

‘Proper’ connective tissue can be divided into:

• __________: has more types

  • eg. ____________

• __________: has less types

  • eg. ____________

• Loose - areolar, adipose, reticular

• Dense - Tendons

Three key examples of cell types within loose connective tissue:

• Fibroblasts

• Fibrocytes

• Mesenchymal Cells

________ secrete the proteins to make up the extracellular matrix while _________ maintain them.

Fibroblasts - fibrocytes

__________ cells are stem cells that divide to replace damaged _________ cells in __________ tissue.

Mesenchymal - fibroblasts - loose proper connective tissue

Extracellular protein fibers in __________ tissue can be:

• ____________: elastic

• ____________: high tensile strength

connective tissue proper

• Elastin

• Collagen

Tissue membrane = ____________ + _____________

epithelial tissue + underlying connective tissue

Layer of connective tissue not directly connected to the epithelium:

Fascia

Layers of connective tissue surrounding organs to provide physical support:

Fascia

Connective tissue repairs through:

increased secretion of fibers

Epithelial tissue repairs through:

Rapid proliferation

When connective tissue is injured:

• First a ______ forms out of ________

• Then a ________ forms when ___________ is secreted

• clot - blood tissue

• scar - web of collagen fibers

The integuments two main components are:

cutaneous membrane + accessory structures

What does the cutaneous membrane include and what does it not?

epidermis + dermis, doesn’t include the hypodermis

What are the four main functions of the integument?

• Barrier to immune + osmotic homeostasis

• Vitamin D and Ca2+ homeostasis

• Sense organ

• Thermal homeostasis

What kind of tissue is the epidermis? What is it divided into?

stratified squamous epithelium - strata

Epidermal ____ cells are:

1. proliferated in the stratum _________

2. differentiate into ______ in the stratum _________

3. lose their organelles in the stratum _________

basal

1. basale

2. keratinocytes - spinosum

3. granulosum

What are epidermal cells filled with and why?

• Keratin - tough, water resistant protein

• Limits insensible perspiration

What is the function of melanin?

absorbs UV photons to prevent DNA UV damage

_______ produces melanin within the stratum ________ and ships it within __________ via _______ transport to __________

• melanocytes

• basale

• melanosomes

• vesicular

• keratinocytes

The dermis contains two layers of connective tissue:

• Stratum Papillare

• Stratum reticulare

The stratum papillare is within the _______ and is composed of ___________________ tissue

dermis - loose proper connective tissue/ areolar tissue

The stratum reticulare is within the _______ and is composed of ___________________ tissue

dermis - dense and elastic irregular connective tissue

The 4 phases of integument repair:

1. Inflammatory

2. Migratory

3. Proliferation

4. Scarring

Inflammatory phase:

• ________ cells stimulate inflammation

• _______ occurs
  
  

• immune phagocytic

• bleeding

• Describe what happens it the migratory phase for:

  • Dermis:

    • Formation of _______ tissue which includes:

  • Epidermis: ________________

• Dermis: Granulation tissue = new blood vessels, mesenchymal cells, fibroblasts

• Epidermis: basal cells proliferate along wound edges, scab is formed

What happens during the proliferation phase for:

• Epidermis: ___________

• Dermis: _____________ and _____+_____ are produced by ____________

• normal division

• deeper blood clot dissolved - collagen fibers + ground substance - fibroblasts

Scarring phase: ______ scar tissue is formed by the process of ___________ in the dermis.

fibrous - activation, enhanced collagen secretion

What causes the formation of keloids?

very rapid proliferation and secretion from fibroblasts

A callus is the thickening of the ____________ caused by _____________ ____________

stratum corneum - strongly cross-linked keratinocytes

Where are accessory structures embedded?

Dermal layers

Three examples of accessory structures in the integument:

• Somatosensory neurons (touch)

• Nociceptive neurons (pain)

• Glands

Sweat glands can be:

• _________: in axillary and pubic regions

• _________: everywhere else

• Apocrine

• Eccrine

Which accessory structures maintain thermal homeostasis and provide a barrier for the skin?

• Barrier: sebaceous glands

• Thermal homeostasis: sweat glands

How does skin play as an effector in thermal homeostasis?

• Evaporative cooling

• Radiant cooling: blood circulation reaches skin surface

• Radiant heating: blood circulation avoids surface to retain heat

The _________ maintains calcium levels by __________.

epidermis - synthesizing vitamin D

• Vitamin D is produced when sunlight reacts with a __________ in the epidermis.

• From a liver intermediary product, the kidneys produce __________.

• This hormone then: __________________

• steroid

• calcitriol

• stimulates Ca absorption in small intestines

Why are darker skin tones likely to have lower vitamin D levels?

The melanin absorbs more UV, leaving less available to react with steroids. Yet, they have less cell damage.