Module 3 Microbiology and Integumentary

Key features of Eukaryotes

Possess a true nucleus, DNA enclosed in a nuclear membrane

Multiple chromosomes

Membrane bound organelles present

Cell wall absent except plants (cellulose) fungi (chitin)

Reproduce cells using mitosis

Key features of Prokaryotes

No true nucleus, DNA not within a membrane

One continuous chromosome

No membrane bound organelles

Posses a cell wall, contains peptidoglycan

Reproduce using binary fission

Acellular microorganisms

Microorganisms without cellular structure (like viruses)

Are dependent on a host to replicate (obligate parasites)

Use the hosts resources

Positive impact of microorganisms

They help with digestion, produce vitamins, and protect against pathogenic microbes by competing for resources.

Negative impact of microorganisms

They can cause infections and diseases. Contribute to food spoilage and contamination

What is Normal flora

Microorganisms normally found on or in the body that help maintain health.

What is Resident flora

Permanent microorganisms found on the body.

What is Transient flora

Temporary microorganisms that are often removed by washing.

Effect of resident flora on immunity

They prevent colonization by harmful microbes and stimulate the immune system.

What is Sterilisation

The complete elimination of all microorganisms, including spores.

What is Disinfection

The use of chemicals to eliminate most pathogens (excluding spores) on surfaces.

What is Antisepsis

The application of antimicrobial substances to living tissue to reduce infection risk.

Purpose of Antimicrobial drugs

Medications used to kill or inhibit the growth of microorganisms.

Functions of the skin

Protection, temperature regulation, sensation, metabolism (vitamin D production), excretion, and immunity.

Layers of the skin

Epidermis (outermost layer), dermis (middle layer), hypodermis (deepest layer).

Cells in the epidermis

Keratinocytes (protective protein), melanocytes (skin colour, UV protection), Langerhans cells (immunity), and Merkel (tactile) cells.

Layers of the epidermis

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum (only in thick skin), stratum corneum.

Function of the stratum basale

Cell regeneration; contains stem cells that divide to form keratinocytes.

Function of the stratum corneum

Provides a tough, water-resistant barrier with dead keratinized cells.

What is the papillary layer of the dermis composed of?

Loose connective tissue, blood vessels, and sensory receptors.

What is the reticular layer of the dermis composed of?

Dense regular connective tissue. (Strength and elasticity).

Layers of the dermis

Papillary layer and reticular layer

Tissue in the hypodermis

Areolar and adipose tissue. (Insulation and energy storage)

Structures in the dermis

Blood vessels, nerve endings, hair follicles, sebaceous (oil) and sweat glands.

Function of sebaceous glands

Secrete sebum to lubricate skin and hair, and prevent microbial growth.

Types of sweat glands

Eccrine (palms, soles, forehead); Apocrine (armpits, groin).

Cause of body odor

Bacterial breakdown of sweat from apocrine glands.

Role of arrector pili muscles

Contract to cause 'goosebumps,' helping to trap air for insulation.

Role of nails

Protection and as tools for scratching and grasping.

Stages of wound healing

Haemostasis, inflammation, proliferation (reconstruction), and maturation (remodeling).

Function of the stratum spinosum

Provide strength and flexibility to the skin

Function of stratum granulosum

Transition layer between dead and alive. Where kerantinisation begins

Function of stratum lucidum

Thick skin (palms, soles). Protection from wear and tear.