Class 6 - Human Tissues pt. 2

Question 1

Connective tissue + 5 types

Answer 1

Most abundant and variable tissue, more matrix space.
Most cells not in direct contact with each other.
Highly variable vascularity

1. fibrous
2. adipose
3. cartilage
4. bone
5. blood

Question 2

8 functions of connective tissue

Answer 2

1. Binding of organs - Connect bones and muscles, skin to muscle, hold organs in place.
2. Support - Internal framework of organs
3. Physical protection - Cushion delicate organs
4. Immune protection - Attacks foreign invaders.
5. Movement - Bones provide lever system, cartilage involves speech
6. Storage - Maintain stores of fat, calcium, and phosphorus
7. Heat production - Metabolism of brown fat generates heat
8. Transport - Blood transports gases, nutrients, wastes, hormones, blood cells

Question 3

Components of fibrous connective tissue (6)

Answer 3

1. Fibroblasts - Produce fibers and ground substance matrix
2. Macrophages - Arise from monocytes; phagocytize foreign material; activate immune system (antigens)
3. Leukocytes (white blood cells) - Immune defense
4. Plasma cells - Arise from lymphocytes and synthesize antibodies
5. Mast cells - Secrete heparin to inhibit clotting; histamine to dilate blood vessels.
6. Adipocytes (fat cells) - Clustered in some fibrous tissues = adipose tissue

Question 4

3 fiber types of fibrous connective tissue

Answer 4

1. Collagenous (white fibers) - Tough, flexible, stretch-resistant. Tendons, ligaments, and deep skin layer
2. Reticular - Thin collagen fibers coated with glycoprotein. Framework of spleen and lymph nodes, part of basement membranes under epithelia.
3. Elastic - Thinner, allows stretch and recoil.

Question 5

Components of ground substance (3)

Answer 5

1. Glycosaminoglycans
2. Proteoglycans
3. Adhesive glycoproteins

Question 6

Loose fibrous connective tissue + two types

Answer 6

Mostly ground substance in space surrounding cells.

1. Areolar - Abundant blood vessels, all six cell and fiber types; underlies epithelia in serous membranes, between muscles, passageways for nerves/blood vessels
2. Reticular - Has fibroblasts, forms supportive stroma (framework) for lymphatic organs. Found in lymph nodes, spleen, thymus, bone marrow

Question 7

Dense fibrous connective tissue + 2 types

Answer 7

Mostly fibers in space surrounding cells.

1. Regular - parallel collagen fibers, compressed fibroblasts nuclei. Tendons attach muscles to bones and ligaments hold bones together. Withstands stress from one direction.
2. Irregular - Randomly arranged. Collagen fibers and few visible cells. Withstands stress from all directions. Located in deep skin layer and capsules around organs

Question 8

Adipose tissue (fat) + 2 types

Answer 8

Space between adipocytes occupied by areolar tissue, reticular tissue, and blood capillaries.
Body’s primary energy reservoir.
Fat recycled continuously

1. White adipose tissue - Most abundant. Provides thermal insulation. Cushions organs (eyes, kidney). Secretes hormones that regulate metabolism.
2. Brown adipose tissue - Mainly in children/infants. Color from blood vessels, mitochondria, mitochondrial enzymes. Heat generating.

Question 9

Cartilage tissue + 3 types

Answer 9

Stiff connective tissue with flexible, rubbery matrix. Gives shape to ear, nose tip, larynx.
Avascular, diffusions brings nutrients/waste
Matrix rich in GAGs and contains collagenous fibers

Types:
1. Hyaline - clear, glassy. Eases joint movement, holds open airway, moves vocal cords, growth of juvenile long bones.
Locations: articular cartilage, costal cartilage, trachea, larynx, fetal skeleton

2. Fibrocartilage - Large coarse bundles of collagen fibers. Resists compression and absorbs shock.
   Locations: Pubic symphysis, menisci, intervertebral discs.
3. Elastic cartilage - covered with perichondrium, flexible elastic support.
   Locations: external ear and epiglottis.

Question 10

Bone (osseous tissue) + 2 forms

Answer 10

Calcified connective tissue that composes the skeleton.

1. Spongy bone - Delicate slivers and plates. Head of long bones and in middle flat bones (sternum)
2. Compact (dense) bone - Calcified tissue with no visible spaces. External surface of all bones

Question 11

Features of compact bone (6)

Answer 11

1. Central (osteonic canal) - Passage running longitudinally along bone shaft, contains blood vessels and nerves
2. Concentric lamellae - Ringlike layers of bone surrounding central canal
3. Osteon - Central canal and its surrounding lamellae
4. Osteocytes - Mature bone cells within lacunae between lamellae.
5. Canaliculi - Delicate canals radiating from each lacuna to its neighbors, allowing osteocytes to contact each other.
6. Periosteum - Tough fibrous connective tissue covering whole bone

Question 12

Blood

Answer 12

Fluid connective tissue that travels through tubular blood vessels. Transports cells and dissolved matter from place to place.

Contains formed elements suspended in a liquid ground substance called blood plasma

Question 13

What formed elements include (3)

Answer 13

1. Erythrocytes (red blood cells) - Transport O2 and CO2z
2. Leukocytes (white blood cells) - defend against infection/disease
3. Platelets - Cell fragments involved in clotting. No nuclei

Question 14

Excitability

Answer 14

Ability to respond to stimuli by changing membrane potential.
Most developed in nervous and muscular tissues.

In nerve cells —> transmission of signals
In muscle cells —> Contraction/shortening of cell

Question 15

Nervous tissue + 2 components

Answer 15

Specialized for communication by electrical and chemical signals.

1. Neurons (nerve cells) - detect stimuli, respond quickly, transmit coded info
2. Neuroglia (glial cells) - Protect and assist neurons.

Question 16

Muscle tissue + 3 types

Answer 16

Specialized to contract when stimulated, exerting physical force.

1. Skeletal - Long fibers, most attaches to bone, multinucleated, striations, voluntary
2. Cardiac - Heart wall, short and branched, one nucleus, intercalated discs join cardiomyocytes end to end, striated, involuntary
3. Smooth - short fusiform cells, one nucleus, most is visceral (walls of hollow organs), no striations, involuntary.

Question 17

3 Features of cartilage tissue

Answer 17

Features:
1. Chondroblasts - Cartilage cells that produce the matrix

2. Chondrocytes - Cartilage cells trapped in lacunae
3. Perichondrium - Sheath of dense irregular connective tissue that surrounds elastic and most hyaline cartilage (not articular). Contains reserve of chondroblasts for future.