240919 Intro to cells, tissues and neoplasia

Question 1

What are the 3 germ layers human cells develop into and what tissues do they comprise?

Answer 1

• Ectoderm: SKIN & NERVOUS SYSTEM
• Mesoderm: MUSCULOSKELETAL SYSTEM & CONNECTIVE TISSUE
• Endoderm: LININGS OF DIGESTIVE & RESPIRATORY SYSTEM PLUS ORGANS SUCH AS LIVER, PANCREAS

Question 2

What are the 4+ phases of cell division and what happens in each?

Answer 2

Gap 1 (G1): synthesis of proteins and organelles for daughter cell
»> G0: state that specialised cells are in

Synthesis (S): replication of DNA

G2: more protein synthesis and regulation of cell cycle (e.g. checking for errors in genetic code, then repair of these errors or termination of cell division process).

Mitosis (M): cell division comprising anaphase, metaphase etc.

Question 3

Name and define the two ways in which cells die

Answer 3

1. Apoptosis (programmed/regulated cell death): Cell fragments into smaller, cell-like bits (thereby keeping the hydrolytic enzymes contained) which are then engulfed and destroyed.
2. Necrosis (unregulated cell death): cell is ruptured, thereby causing inflammation – which, along with thrombosis, clotting, and neoplasia (tumour growth, underlies almost all human diseases.

Question 4

Name and define 3 ways in which cell division can go wrong

Answer 4

Hyperplasia = too many cells are created

Hypertrophy = cells become too big

Metaplasia = mature, specialised cells turn into other types of specialised cells

Question 5

Provide the 3 elements that define ‘Neoplasia’

Answer 5

Abnormal cell growth

in an unregulated manner

persisting without stimulus

Question 6

What is the basement membrane and what’s its relevance when distinguishing between benign and malignant tumours?

Answer 6

The basement membrane is a thin, dense layer of extracellular matrix that lines most human tissues, forming the supporting structure and scaffolding for epithelial tissue.

If the basement membrane confines a tumour, it remains benign. Malignant tumours break out of the basement membrane and thereby become “invasive”.

Question 7

Use 8 features to distinguish between the characteristics of benign tumours and malignant tumours.

Answer 7

Growth rate: (B) Slow, (M) fast

Border: (B) smooth/encapsulated, (M) irregular)

Infiltration and spread: (B) confined by basement membrane, (M) invasive locally and distant spread

Shape: (B) smooth/round, (M) speculate/asymmetrical

Differentiation: (B) well differentiated, (M) poorly differentiated

Treatment: (B) surgery, (M) surgery, radiotherapy, chemotherapy, immunotherapy

Recurrence: (B) low chance, (M) high chance if not fully removed

Prognosis: (B) often good, (M) often bad

Question 8

Name both the benign and malignant versions of tumours that have formed from the gland-like cells of epithelial tissue?

Answer 8

Adenoma and adenocarcinoma

Question 9

Name the five most common types of cancer

Answer 9

• Breast adenocarcinoma (vast majority of breast cancers)
• Prostate adenocarcinoma
• Lung adenocarcinoma
• Lung squamous cell carcinoma
• Colorectal adenocarcinoma

Question 10

Provide the 4 elements that define ‘dysplasia’

Answer 10

Abnormal cell growth

in an unregulated manner

persisting without stimulus

but does not invade/has not invaded

Question 11

State the 4 ways in which cancer spreads

Answer 11

1. Local spread – through basement membrane and into nearby tissues
2. Lymphatic spread – travels through lymph system
3. Haematogenous spread – travels through blood vessels
4. Trans-coelomic spread – through a body cavity

Question 12

Name four ways in which cancer harms the body

Answer 12

• Destroys normal tissue as it grows
• Bleeds easily
• Uses up a lot of energy
• Undergoes necrosis if the energy runs out (causing inflammation etc.)