Introduction to the human body

Question 1

What are the four muscle tissues in the body?

Answer 1

• Epithelial
• Muscular
• Connective
• Tissue

Question 2

What are the different levels of organisation in the body?

Answer 2

• Organism level
• System level
• Organ level
• Tissue level
• Cellular level
• Organelle level
• Molecular level
• Mitochondria level
• Atomic level

Question 3

Define interdependence

Answer 3

• Organisms depend on each other for survival

Question 4

Describe homeostasis.

Answer 4

• The ability for the body to maintain a stable internal environment despite a changing external environment.
• The body maintains homeostasis through feedback loops.

Question 5

What does the body regulate to maintain a stable internal environment?

Answer 5

• Temperature
• Ion concentration
• Salinity
• Oxygen levels
• pH

Question 6

What does a feedback loop involve?

Answer 6

• A receptor (sensor that monitors the environment and responds to the stimulus) sends info to the control centre (determines appropriate response) and then relays information to the effector (carries out response and brings body back to balance).

Question 7

Explain the difference between positive feedback loop and negative feedback loop.

Answer 7

• Negative: keeps internal environment stable by decreasing hormone production.
• Positive: keeps internal environment stable by increasing hormone production.

Question 8

What are the four primary tissue classes? Describe them.

Answer 8

• Nervous= Excitable, specialised for rapid signal conduction.
• Muscular= Excitable, specialised for contraction.
• Epithelial= Covers organs. Protects, secretes and absorbs.
• Connective= Protects, binds and supports.

Question 9

What are the three main types of simple epithelial tissue? Describe them.

Answer 9

• Squamous= Description: flat like cells. Function: filtration, secrete lubricating surfaces. Location: Kidney glomeruli, heart walls, blood vessels, alveoli, lymphatic vessels.
• Cuboidal= Description: Cube like cells. Function: secretion/ absorption. Location: kidney tubules, ovary surfaces, small glands.
• Columnar= Description: Tall cells, cilia/ microvilli. Function: Secretion/ absorption. Location: Digestive tract, gall bladder, gland ducts.

Question 10

Briefly explain stratified epithelia.

Answer 10

• Two or more cell layers
• Regenerative from below
• More durable than simple epithelia
• Physical protection is a major role.

Question 11

What are the main types of connective tissue?

Answer 11

• Connective tissue proper
• Blood
• Bone
• Cartilage

Question 12

What are the functions of connective tissue?

Answer 12

• Physical Protection
• Immune protection
• Heat production
• Transport
• Support
• Storage
• Binding organs
• Movement

Question 13

What are the cells in connective tissue?

Answer 13

• Blast (builder) cells, secrete ground substance and fibres = Osteoblasts in bone, Chondroblasts in cartilage and fibroblasts in connective tissue proper.
• Clast (remodelling) cells break down connective tissue = Osteoclasts in bone and chondroclasts in cartilage.
• Cyte cells (control activity of blast and clast cells= Osteocytes in bone, chondrocytes in cartilage. Chondrocytes are important in forming cartilage.

Question 14

What are the main connective tissue proper types, briefly describe them.

Answer 14

• Areolar: fibres moving through ground substance
• Dense: Ground substance plus cells and fibres (collagen)
• Adipose: Not much ground substance but fine matrix of fibres surrounding adipocytes.

Question 15

What is ground substance?

Answer 15

• Mainly water and hydroscopic proteoglycans. Lacunae maintain the ground substance.

Question 16

What are the different types of cartilage?

Answer 16

• Hyaline cartilage: found in synovial joints of the body, creating articulating surfaces at end of bones so they don’t rub against each other and create friction, also acts as a shock absorber. It has a perichondrium which is a connective tissue that surrounds cartilage and produces chondrocytes and chondroblasts. It also has lacunae which contains chondrocytes.
• Elastic cartilage is found in the inner ear. It contains chondrocytes, lacunae, ground substance and fibres.
• Fibrocartilage is fibrous and has lots of collagen and elastin fibres. The fibres act as good shock absorbers. E.g., in-between vertebral discs.

Question 17

What is bone and what does it contain?

Answer 17

• Is a strong, rigid ground substance.
• It contains: Lacunae, osteocytes, periosteum, osteons, haversian canals.

Question 18

Briefly describe blood

Answer 18

• Blood cells are suspended in plasma: Red blood cells (erythrocytes) and white blood cells (lymphocytes and neutrophils).
• Blood contain: Cells, matrix and fibres.

Question 19

What does nervous tissue contain?

Answer 19

• Neurons
• Glial cells: protect and assist neurons, help regulate the chemical/ physical environment.

Question 20

What are the main components of connective tissue?

Answer 20

• ground substance/ matrix
• cells
• fibres (collagen/ elastin)

Question 21

What are the two remaining tissue classes of the body?

Answer 21

• Nervous= has neurone and glial cells.
• Muscular= three types: skeletal (voluntary), cardiac (involuntary) , smooth (involuntary).

Question 22

Explain epithelial tissue=

Answer 22

• epi (on or covering, thelium (layer)
• Functions: secretion, filtration, protection, absorption, sensation
• Structural classification: simple, stratified

Question 23

Cartilage=

Answer 23

• Tough, flexible, rigid
• Up to 80% water
• Lacks nerves and blod vessels