Unit 6 Lymphatic and Integumentary CRs

What are the 5 layers of the epidermis? What is the main characteristic of each layer?

Basale: Deepest, stem cells, melanocytes, Merkel cells

Spinosum: Spiny, desmosomes, Langerhans

Granulosum: Keratin, waterproofing, cells start dying

Lucidum: Clear, dead cells, only in thick skin

Corneum: Dead, flat keratinized cells, protection, water loss barrier

Explain how the 1st, 2nd, and 3rd lines of defense work.

1st: Physical/chemical barriers (skin, mucus, acid, tears)

2nd: Innate; inflammation, fever, phagocytes, NK cells

3rd: Adaptive; B cells (antibodies), T cells (kill/help/suppress)

What is the flow of lymph back to the heart?

Capillaries to Vessels to Nodes to Trunks to Ducts to Subclavian veins to Heart
aided by valves, muscle contractions

What are the 3 types of effector T cells and what is the function of each?

Cytotoxic: Kill infected/cancerous cells

Helper: Activate B cells, cytotoxic T, macrophages

Regulatory: Suppress immune response, prevent autoimmunity

What do Natural Killer (NK) cells do and how do they work?

Innate immunity, kill virus infected/tumor cells

Target cells lacking MHC I

Use perforin (pores) + granzymes (apoptosis)

What do cytotoxic T cells do and how do they work?

Adaptive immunity, recognizes MHC I + antigen

Kill infected cells with perforin + granzymes

Evolutionarily, what is happening with antibiotic resistance? Why would someone at first start to feel better on an antibiotic and then start to feel bad after a few days?

Natural selection: Resistant bacteria survive and multiply

Feel better as weak bacteria die, feel worse if resistant ones regrow

Resistance spreads, making treatment harder