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Anatomy and Physiology I > Unit 2 LOs > Flashcards

Unit 2 LOs Flashcards

1
Q

Name the four primary classes into which all adult tissues are classified.

A

Epithelial tissue, connective tissue, nervous tissue, and muscular tissue

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2
Q

Define histology

A

The study of tissues

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3
Q

Compare the general features of the four major tissue types.

A

All 4 tissues types are similar to each other in the following ways:
All tissue types are made up of cells.
All tissue types have an extracellular matrix
All cells and tissues occupy space

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4
Q

Contrast the general features of the four major tissue types.

A

The 4 tissue types vary in:
The types and functions of their cells
The characteristics of their matrix (extracellular material)
The relative amount of space occupied by their cells versus their matrix

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5
Q

Describe the unique functions of the epithelium

A
  • It covers body surfaces and lines body cavities
  • It protects deeper tissues from injury and infection
  • It produces and releases chemical secretions; also involved with excretion and absorption
  • It selectively filters substances
  • It makes up most glands
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6
Q

Describe the unique characteristics of epithelium

A
  • Its cells are very close together
  • Its cells have a high rate of mitosis (regenerative)
  • Has apical and basal surfaces
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7
Q

Name and describe the 4 types of simple epithelium

A

1) Simple squamous
Permits rapid diffusion or transport of substances
It secretes serous fluid
Found in: air sacs of lungs (alveoli), inner lining of blood vessels & heart (endothelium), and serosa
2) Simple cuboidal
It’s good at absorption and secretion, mucus production, and movement
Found in: Kidney tubules and certain glands (thyroid, mammary and salivary glands)
3) Simple columnar
Specializes in absorption and secretion; secretion of mucus
Has a brush border of microvilli, ciliated in some organs, and may possess goblet cells. It’s the only tissue with microvilli.
Made up of a single row of tall, narrow cells; oval nuclei in basal half of cell
Found in: the lining of the GI tract, the uterus, and uterine tubes
4) Pseudostratified columnar
Secretes and propels mucus
Has cilia and goblet cells
Looks multilayered, but all cells touch the basement membrane
Has nuclei at several layers
Found in the respiratory tract

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8
Q

Describe stratified squamous epithelium

A

The most widespread epithelium in the body
Deepest layers undergo continuous mitosis
Daughter cells push toward the surface and become flatter as they migrate upward, and the top layer is exfoliated

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9
Q

Name and describe the two types of stratified squamous epithelium

A

1) Keratinized stratified squamous epithelia
Resists abrasion; retards water loss through skin; resists penetration by pathogenic organisms.
Top layer of cells are dead.
Locations: epidermis; palms and soles heavily keratinized
2) Non-Keratinized stratified squamous epithelia
Resists abrasion and penetration of pathogens
Top layer of cells is not dead.
Locations: tongue, oral mucosa, esophagus, and vagina

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10
Q

Name the two main types of stratified epithelia. Can these be broken down into more types?

A

Stratified squamous epithelia and transitional epithelia. There are two types of stratified squamous epithelia: keratinized and non-keratinized.

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11
Q

Describe transitional epithelia and where it’s located

A

A type of stratified epithelia that permits stretching (distension); surface cells change from round to flat when stretched
Locations: ureter and urinary bladder

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12
Q

Describe the properties that most connective tissues have in common.

A

-Their cells occupy less space than matrix (usually there’s a large amount of extracellular matrix)
-Most of their cells are not in direct contact with each other
-They have a highly variable vascularity
(Loose connective tissues have many blood vessels whereas cartilage has few or no blood vessels)

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13
Q

What is the most diverse and abundant type of tissue

A

Connective tissue

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14
Q

Discuss the types of cells found in connective tissue.

A

1) Fibrous Connective Tissue (Connective Tissue Proper)
Made up of fibers (collagen, reticular, and elastic fibers) and ground substance of the matrix produced by fibroblasts.
2) Adipose Tissue
Adipocytes (fat cells) contain a large amount of space reserved for storing fats.
3) Cartilage
Chondroblasts form the matrix, which is then occupied by chondrocytes (cartilage cells)
4) Bone (Osseous tissue)
Osteoblasts form the matrix, which is then occupied by osteocytes.
5) Blood
Made up of plasma, platelets, WBCs, and RBCs.

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15
Q

What are the two main types of fibrous connective tissue? Can they be broken down into further categories.

A

Loose and dense connective tissue are the two main types. The two types of loose fibrous connective tissue are areolar and reticular. The two types of dense connective tissue are dense regular and dense irregular

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16
Q

Define and describe areolar tissue. Also, where is it found?

A
  • One of the two types of loose connective tissue, which is a type of fibrous connective tissue.
  • All 3 fibers/ 6 total cell types are found; loosely organized; abundant blood vessels; lots of empty space.
  • Mostly collagenous, but elastic and reticular also present
  • Wraps & cushions organs; underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels
  • Fibers run in random directions
  • Found in tissue sections from almost every part of the body
  • Surrounds blood vessels and nerves
  • Nearly every epithelium rests on a layer of areolar tissue
  • Blood vessels provide nutrition to epithelium and waste removal
  • Ready supply of infection-fighting leukocytes that move about freely in areolar tissue
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17
Q

Define and describe reticular tissue. Also, where is it found?

A
  • One of the two types of loose connective tissue, which is a type of fibrous connective tissue.
  • Mesh of reticular fibers and fibroblasts
  • Forms supportive framework for lymphatic organs
  • Found in lymph nodes, spleen, thymus, and bone marrow
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18
Q

Define and describe dense regular tissue

A
  • One of the two types of dense connective tissue, which is one of the types of fibrous connective tissue.
  • Densely packed, parallel collagen fibers
  • Tendons attach muscles to bones and ligaments hold bones together
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19
Q

Define and describe dense irregular tissue

A
  • Dense, randomly arranged, collagen fibers
  • Withstands unpredictable stresses
  • Locations: reticular layer of dermis; organ capsules
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20
Q

Describe adipose tissue

A
  • A type of connective tissue
  • Space between adipocytes occupied by areolar tissue, reticular tissue, and blood capillaries.
  • The quantity of stored triglyceride and the number of adipocytes are quite stable in a person.
  • Fat is recycled continuously; new triglycerides synthesized while old molecules hydrolyzed and released to blood
  • Functions: Energy storage, insulation, cushioning
  • Fat is the body’s primary form of energy storage.
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21
Q

Describe cartilage

A

Stiff connective tissue with flexible matrix; chondroblasts produce the matrix that will trap them in lacunae (cavities) and become chondrocytes.
Contains reserve population of chondroblasts

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22
Q

List and describe the 3 types of cartilage and where they can be found

A

1) Hyaline cartilage
Clear, glassy appearance because of fineness of collagen fibers
Surrounded by perichondrium
Locations: articular cartilage, costal cartilage, respiratory cartilage, fetal skeleton
2) Elastic cartilage
Contains abundant elastic fibers; covered with perichondrium
Provides flexible, elastic support
Locations: external ear and epiglottis
3) Fibrocartilage
Contains large bundles of collagen fibers; no perichondrium.
Resists compression and absorbs shock
Locations: pubic symphysis, menisci of knee, and intervertebral discs

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23
Q

Describe bone (osseous tissue)

A

Has a hard calcified matrix with collagen fibers; made by osteoblasts who build and become osteocytes in lacunae. A type of connective tissue

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24
Q

Describe the two types of bone (osseous tissue)

A

1) Spongy bone
Porous appearance with visible holes.
2) Compact bone
Compact bone is arranged in cylinders that surround central canals that run longitudinally through shafts of long bones

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25
Q

Describe blood

A

-A fluid connective tissue
-Transports cells and dissolved matter from place to place
-Plasma—blood’s ground substance
Formed elements—cells and cell fragments:
-Erythrocytes—red blood cells (RBCs)
-Leukocytes—white blood cells (WBCs)
-Platelets—cell fragments involved in clotting

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26
Q

Explain what distinguishes excitable tissues from other tissues.

A

They have the ability to respond to stimuli by changing membrane potential.

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27
Q

Name the cell types that compose nervous tissue.

A

Neurons and neuroglia.

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28
Q

Identify and describe the major parts of a nerve cell.

A 
1) Neurosoma (cell body)
Contains nucleus & other organelles
Controls protein synthesis
2) Dendrites
Multiple short, branched processes
Receive signals from other cells
Transmit messages to neurosoma
3) Axon (nerve fiber)
Sends outgoing signals to other cells
Can be more than a meter long
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29
Q

Name the three kinds of muscular tissue and describe them

A

1) Skeletal:
Long thin cells called muscle fibers; multinucleate
Most skeletal muscles attach to bone
Striations—alternating dark and light bands
They only type of muscle that is voluntary, meaning conscious control over skeletal muscles.
2) Cardiac:
Cardiomyocytes are branched, shorter than skeletal muscle fibers; uninucleate
Intercalated discs join cardiomyocytes end to end
Provide electrical and mechanical connection
Striated and involuntary (not under conscious control)
3) Smooth:
Short, fusiform myocytes; uninucleate
Non-striated and involuntary
Most is visceral muscle—making up parts of walls of hollow organs

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30
Q

Define cell junctions and describe what they do

A

Cell junctions are connections between two cells; most cells are anchored to each other through a cell junction or their matrix
Cells communicate with each other, resist mechanical stress, and control what moves through the gaps between them

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31
Q

List and describe the 3 types of cell junctions

A

1) Tight junctions:
Seals off intercellular space, making it difficult for substance to pass between cells
Found in the epidermis, stomach, and small intestines
2) Desmosomes
A type of cell junction that keeps cells from pulling apart—resist mechanical stress.
Found in cardiac muscle, the uterine cervix, and the epidermis
3) Gap junctions
Formed by ring-like connexons; the cells now share part of their cell membrane.
Ions, nutrients, and other small solutes pass between cells
Found in cardiac and smooth muscle, embryonic tissue, lens and cornea

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32
Q

Describe the two main kinds of glands

A

1) Exocrine glands: maintain their contact with surface of epithelium by way of a duct
Their surfaces can be external (examples: sweat, tear glands) or internal (examples: pancreas, salivary glands)
Classified by duct shape and gland shape.
2) Endocrine glands: have no ducts; secrete hormones directly into blood
Examples: thyroid, adrenal, and pituitary glands.

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33
Q

Describe unicellular glands and give examples

A

Found in an epithelium that is predominantly nonsecretory; can be exocrine or endocrine
Examples: mucus-secreting goblet cells in trachea or endocrine cells of stomach

34
Q

Define a gland and describe its typical anatomy

A
  • A gland is defined as a cell or organ that secretes substances for use elsewhere in the body or releases them for elimination from the body
  • They are usually composed of epithelial tissue with a connective tissue framework and capsule
35
Q

Name and describe the three different modes of glandular secretion.

A

1) Merocrine
Uses vesicles that release their secretion by exocytosis.
Used by eccrine glands.
2) Apocrine
Lipid droplet covered by membrane and cytoplasm buds from cell surface
Mode of milk fat secretion by mammary gland cells
3) Holocrine
Cells accumulate a product until they disintegrate (entire cell dies and is secreted, hence why these glands’ substances are oily)
Secrete a mixture of cell fragments and synthesized substances
Ex: sebaceous glands of hair and skin, eyelid glands.

36
Q

Describe the types and composition of the body’s membranes.

A

1) Cutaneous membrane (the skin)
Largest membrane in the body
Stratified squamous epithelium (epidermis) resting on a layer of connective tissue (dermis)
Relatively dry layer serves protective function
2) Mucosal membranes
Layers consists of epithelium, areolar tissue (lamina propria), and smooth muscle (muscularis mucosa)
An internal membrane that lines cavities/passages that open to the external environment
Produces mucus (thicker, stickier)
This membrane can be found in 4 organ systems: reproductive, digestive, respiratory, and urinary.
3) Serous membranes
Composed of simple squamous epithelium resting on a layer of areolar tissue
Internal membrane; lines cavities with no connection to the outside
Produces serous fluid
4) Membranes made of only epithelium:
Anterior surfaces of cornea and lens of eye
5) Membranes made of only connective tissue:
Dura mater (meninges), synovial membranes, periosteum, perichondrium

37
Q

Name and describe the modes of tissue growth.

A

1) Hyperplasia: growth through cell multiplication
2) Hypertrophy: enlargement of preexisting cells
Examples: muscle growth through exercise, accumulation of body fat
3) Neoplasia: development of a tumor (neoplasm)
Tumor can be benign or malignant
Composed of abnormal, nonfunctional tissue

38
Q

Name and describe the ways the body repairs damaged tissues.

A

1) Regeneration: replacement of dead or damaged cells by the same type of cell as before
Restores normal function
Examples: repair of minor skin or liver injuries
2) Fibrosis: replacement of damaged cells with scar tissue
Scar holds organs together, but does not restore function
Examples: repair of severe cuts and burns, scarring of lungs in tuberculosis

39
Q

List the functions of the skin and relate them to its structure.

A

1) Resistance to trauma and infection:
- Keratin
- Dermacidin & defensins
- Acid mantle acts as an antimicrobial barrier.
- There are very few spaces between cells in the epidermis to protect against trauma and infection.
2) Other barrier functions
- Water (protects against dehydration): The stratum corneum is a layer of dead cell membranes, which provides a layer of protection against water.
- UV radiation: melanin aids in UV protection
- Harmful chemicals
3) Vitamin D synthesis
- Skin carries out first step; Liver & kidneys complete process
4) Sensation receptors
- Touch, temperature, pressure, vibration, tickle, itch, and pain sensations
5) Regulation of body temperature
- Thermoreceptors
- Vasoconstriction/vasodilation; if you are too warm, cutaneous blood vessels vasodilate
- Perspiration
6) Nonverbal communication
- Facial expressions
- The color of skin based on factors such as blood flow/ hemoglobin and carotene can display signs of illness without verbal communication.

40
Q

Describe the histological structure of the epidermis, dermis, and subcutaneous tissue.

A

1) The epidermis consists of keratinized stratified squamous epithelial tissue
2) The dermis consists of two layers:
- Papillary layer: A thin layer of areolar connective tissue
- Reticular layer: A thicker layer of dense irregular connective tissue.
3) Subcutaneous tissue: Consists primarily of adipose connective tissue, but also contains areolar connective tissue.

41
Q

Describe the difference between thick and thin skin.

A

Unlike thin skin, thick skin does not contain hair follicles and it has an extra thin white/clear epidermal layer that is not present in thin skin called the stratum lucidum. This causes dermal papillae to be more pronounced in thick skin.

42
Q

Describe the normal and pathological colors that the skin can have

A

1) Cyanosis: blueness due to oxygen deficiency
- Oxygen deficiency is usually due to events that cause respiratory distress. This includes things such as drowning, severe asthma attacks, lung failure, pertussis in infants, choking, etc.
2) Erythema: redness due to increased blood flow to skin.
- Increased blood flow to the skin can be caused by injuries such as heat burns, sunburns, consumption of alcohol, or strong emotions such as embarrassment or anger.
3) Pallor: paleness due to decreased blood flow to skin
- Decreased blood to the skin often happens during or immediately prior to syncope or during illness. Malnutrition can also be a cause of pallor.
4) Albinism: milky white skin and blue-gray eyes due to genetic lack of melanin synthesizing enzyme
- This is only due to genetic mutations and cannot develop during a person’s lifetime after birth.
5) Jaundice: yellowing due to bilirubin in blood (can be caused by compromised liver function)
- Often seen in newborn babies or those with liver failure.
6) Hematoma: bruising (clotted blood under skin)
- Usually happens due to blunt force to the skin

43
Q

Describe the basic structure of a hair and its accessory structures (piloerector muscle, etc.)

A

1) Bulb: Contains matrix cells (mitotically active cells). Located beneath the surface of the skin and is wider than the rest of the hair.
2) Root: the remainder of the hair in the follicle
Located beneath the surface of the skin and is just above the bulb.
3) Shaft: the portion of the hair that’s above the skin surface
4) Three layers of a hair can be seen in a cross section: Medulla (core), Cortex, Cuticle (outer layer)
5) Hair receptors: Sensory nerve fibers that are entwined with follicles that detect hair movement
6) Piloerector muscle: Smooth muscle that attaches the follicle to dermis; contracts to make hair stand on its end, which causes goose bumps

44
Q

Discuss the basic functions of hair.

A

1) Protection: The hair on your scalp provides your head with more protection against sunburns.
2) Light touch: Hair helps you sense light touch due to the presence of hair receptors.
3) Heat retention: The hair on your head provides an extra layer to trap warm air.
4) Excretion: Sebaceous glands found on hair follicles excrete sebum, which helps keep skin and hair from drying out.

45
Q

Describe the basic structure and function of nails.

A

Nails are clear, hard derivatives of stratum corneum. They’re composed of thin, dead cells packed with hard keratin.
Provides the tops of our fingertips and toes with an extra layer of protection.

46
Q

Name two types of sweat glands, and describe the structure and function of each

A

1) Merocrine sweat glands
- Most numerous type of skin glands
- The gland’s duct opens to the surface of the skin
- Regulates body temperature by allowing for perspiration
2) Apocrine sweat glands
- Found in the regions of the groin, anal region, axilla, areola, and beard (males)
- These glands are inactive until puberty; responds to stress and sexual stimulation
- Ducts lead to nearby hair follicles
- Believed to secrete pheromones

47
Q

Describe the location, structure, and function of sebaceous glands.

A

Most sebaceous glands open into a hair follicle, meaning they aren’t present in thick skin.
They utilize a holocrine secretion style and secrete sebum, which is an oily secretion that keeps skin and hair from becoming dry, brittle, and cracked. It also inhibits the growth of bacteria & fungi (ringworm)

48
Q

Name some other cutaneous glands

A

1

1) Ceruminous glands in external ear canal
- Modified apocrine sweat glands
- Forms earwax (cerumen)
2) Mammary Glands
- Milk-producing modified apocrine sweat glands that develop only during pregnancy
- Two rows of mammary glands can be found in most mammals

49
Q

Describe the three most common forms of skin cancer.

A

1) Basal cell carcinoma
- Most common form of skin cancer, but the least malignant
- Most often on the head, neck, and hands
- Most common in fair-skinned people and the elderly
- Forms from cells in stratum basale
- Lesion is small, shiny bump with central depression and beaded edges
2) Squamous cell carcinoma
- May metastasize if not removed; tends to metastasize to lymph nodes and may become lethal. However, the chance of recovery is good with early detection and surgical removal
- Arises from keratinocytes of stratum spinosum
- Lesions usually found on the scalp, ears, lower lip, or back of the hand
- They typically have a raised, reddened, scaly appearance later forming a concave ulcer
3) Melanoma
- Least common (less than 5% of skin cancers) but very malignant. Can be successfully removed if caught early, but if it metastasizes it is usually fatal
- Skin cancer that arises from melanocytes
- Greatest risk factor: familial history of malignant melanoma
- Highest incidence in men, redheads, and people who had severe sunburn as a child

50
Q

Describe melanomas

A

Least common (less than 5% of skin cancers) but very malignant. Can be successfully removed if caught early, but if it metastasizes it is usually fatal
Skin cancer that arises from melanocytes
Greatest risk factor: familial history of malignant melanoma
Highest incidence in men, redheads, and people who had severe sunburn as a child

51
Q

Describe basal cell carcinoma

A

Most common form of skin cancer, but the least malignant
Most often on the head, neck, and hands
Most common in fair-skinned people and the elderly
Forms from cells in stratum basale
Lesion is small, shiny bump with central depression and beaded edges

52
Q

Describe squamous cell carcinoma

A

May metastasize if not removed; tends to metastasize to lymph nodes and may become lethal. However, the chance of recovery is good with early detection and surgical removal
Arises from keratinocytes of stratum spinosum
Lesions usually found on the scalp, ears, lower lip, or back of the hand
They typically have a raised, reddened, scaly appearance later forming a concave ulcer

53
Q

Describe the three classes of burns.

A

1) First-degree burn
- Involves only the epidermis and heals in days.
2) Second-degree burn
- A partial-thickness burn; involves part of dermis
- May appear red, tan, or white; often blistered and painful
- Takes two weeks to several months to heal and may leave scars
3) Third-degree burn
- A full-thickness burn; involves epidermis, all of dermis, and often some deeper tissues
- Often requires skin grafts
- Typically requires fluid replacement, infection control, and supplemental nutrition

54
Q

Name the tissues and organs that compose the skeletal system.

A

Major organs: Bones.
Major tissues: Bones are made up of bone tissue, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue

55
Q

Describe the major functions of the skeletal system and give examples

A

1) Support: Limb bones and vertebrae support the body; jaw bone supports the teeth; bones support viscera
2) Protection: Cranial bones protect the brain, vertebrae protect the spinal cord, ribs protect the heart and lungs, etc
3) Movement: Allows for movement of limbs and breathing (requires action of muscles on bones).
4) Electrolyte balance: Helps regulate calcium & phosphate levels
5) Acid–base balance: Buffers the blood against large pH changes by altering phosphate and carbonate salt levels
6) Blood formation: Red bone marrow produces red blood cells.

56
Q

Distinguish between bones as a tissue and as an organ.

A

Bones (organs) have multiple types of tissue; each individual bone in your body is a separate organ.
One of the types of tissue found in bones (organs) is called bone tissue, also called osseous tissue.

57
Q

Describe the types of bones classified by shape and give examples

A

1) Flat bones: cranial bones, sternum, ribs, scapula, hip.
- These bones are usually for protection
2) Long bones: femur, humerus, radius and ulna, metatarsals, metacarpals, digits of manus and pedal regions, etc
- These bones are usually in appendages, for movement
3) Short bones: carpal (wrist) bones, tarsal (ankle) bones
4) Irregular bones: vertebrae, some skull bones (inner ear bones)
5) Sesamoid (type of short bone): patella
- Sesamoid bones develop in a tendon (or ligament) in response to a need for more leverage.
6) Sutural (wormian) bones
- Sutural bones are the extra bones in the sutures (especially the lambdoid suture) of the skull.
- Everyone has a different number of sutures in their cranium (i.e. some people only have 1, while others may have 4, depending on how their cranium formed).

58
Q

Identify the internal structural components of compact bone

A
  • The dense outer shell of bone
  • Made up of subunits called osteons, which contain:
    1) Lamellae
  • Columns of the matrix (mainly collagen) that are weight bearing
  • Run concentric, circumferential, and interstitially
    2) Central (Haversian canal)
  • Contains blood vessels and nerves
    3) Perforating (Volkmann’s) canals
  • Channels that connect blood and nerves from periosteum to the central (Haversian) canal; run transverse or diagonal.
59
Q

Osteons are made up of what 3 components?

A

Lamellae, central (haversian) canal, and perforating (volkmann’s) canals

60
Q

Identify the internal structural components of spongy bone

A
  • A lattice of bone covered with endosteum and an internal honeycomb of trabeculae filled with red or yellow bone marrow
  • Trabeculae (thin plates of bone) develop along the bone’s lines of stress.
  • Spaces filled with red bone marrow
  • Few osteons and no central canals
  • Provides strength with minimal weight
61
Q

Describe and distinguish between the two types of bone marrow.

A

1) Red marrow
- Contains hemopoietic tissue; produces blood cells.
- Found in almost all bones in children, and found primarily in the axial skeleton of adults.
2) Yellow marrow
- Found in adults
- Stores triglycerides; functions as energy storage.
- Can transform back to red marrow in the event of chronic anemia.

62
Q

Describe the intramembranous ossification mode of bone formation

A
  • Bone develops within a fibrous connective tissue membrane
  • Mesenchymal cells&raquo_space;> osteoblasts&raquo_space;> osteocytes (spongy bone)
  • Forms the flat bones of the skull, clavicles, and ossifies the fontanels.
  • Most of these bones are remodeled (destroyed and reformed) as we grow to adult size.
  • Thickens long bones throughout our lives.
63
Q

Describe the endochondral ossification mode of bone formation

A
  • Bone forms by replacing hyaline cartilage
  • Forms most the bones of the body below the skull (except the clavicle)
  • Mesenchyme&raquo_space;turns into» chondroblasts&raquo_space; die and are replaced by&raquo_space; osteoblasts&raquo_space;turn into» spongy bone&raquo_space;turn into» compact bone
64
Q

Compare and contrast the function of osteoblasts and osteoclasts during bone growth, repair, and remodeling.

A
  • Osteoblasts: create bone
  • Osteoclasts: break down bone.
  • During bone growth, osteoblasts create bone. –During bone remodeling, osteoclasts break down bone and osteoblasts create bone.
65
Q

Name and describe the process by which minerals are added to bone tissue.

A
  • Mineral deposition (mineralization): the process in which calcium, phosphate, and other ions are taken from blood and deposited in bone.
  • During this process, osteoblasts produce collagen fibers, and the collagen fibers then become encrusted with minerals.
  • The first few mineral crystals act as “seed crystals” that attract more calcium and phosphate
66
Q

Name and describe the process by which minerals are removed from bone tissue.

A
  • Mineral resorption: the process of dissolving bone and releasing minerals into blood
  • This process is performed by osteoclasts; they pump hydrogen to extracellular fluid (chloride follows). Hydrochloric acid (pH 4) dissolves bone minerals.
  • They also produce an enzyme which digests collagen in an acidic environment.
67
Q

Describe the role of the bones in regulating blood calcium and phosphate levels.

A
  • When blood calcium or phosphate is LOW, the process of mineral resorption takes place. For example, if blood calcium is low, then some of the calcium stored in the bones will be resorbed into the blood stream.
  • When blood calcium or phosphate is HIGH, the process of mineral deposition takes place. For example, if blood calcium is high, then some of the calcium from the blood stream will be deposited into the bones.
68
Q

Explain the role of calcitriol in regulation of bone physiology and describe its effect

A
  • Calcitriol (aka vitamin D) is a hormone that raises blood calcium levels.
  • Mainly, it increases calcium absorption by the small intestine, but it also increases calcium resorption from the skeleton, and weakly promotes kidney reabsorption of calcium ions, so less are lost in urine.
  • It’s produced by actions of skin, liver, and kidneys.
  • Calcitriol is necessary for bone deposition, so lack of calcitriol results in abnormal softness of bones; in children, this causes rickets, and in adults, this causes osteomalacia.
69
Q

Explain the role of calcitonin in regulation of bone physiology and describe its effect

A
  • Calcitonin is produced by the thyroid gland and lowers blood calcium levels; its release is triggered by high blood calcium.
  • It lowers blood calcium concentration in 2 ways; it inhibits osteoclasts and stimulates osteoblasts.
  • It’s important in children, but has a weak effect in adults (except may inhibit bone loss in pregnant and lactating women)
70
Q

Explain the role of parathyroid hormone in regulation of bone physiology and describe its effect

A
  • Parathyroid hormone is produced by the parathyroid glands, and increases blood calcium; its release triggered by low blood calcium.
  • PTH increases blood calcium 4 ways; it stimulates osteoclast population and bone resorption, promotes calcium reabsorption by kidneys, promotes calcitriol synthesis, and inhibits osteoblasts, inhibiting bone deposition
71
Q

Explain the hormonal regulation of skeleton growth.

A
  • Epiphyseal plate activity is stimulated by Human Growth Hormone (hGH); hGH stimulates growth at the epiphyseal plates in children.
  • Estrogen has a stronger effect on skeleton growth than testosterone; both of those hormones begin to affect bone growth during puberty, and they differentiate the male and female skeleton.
  • Males typically continue to grow for a longer period of time than females.
  • At least 20 or more hormones, vitamins, and growth factors affect osseous tissue.
  • Anabolic steroids administered during childhood/ adolescence can also prematurely stop bone growth.
72
Q

Describe the bone disease ostoporosis

A
  • The most common bone disease
  • Affects spongy bone the most since it is the most metabolically active
  • Subject to pathological fractures of hip, wrist, and vertebral column
  • Kyphosis (widow’s hump): deformity of spine due to vertebral bone loss
  • Complications of loss of mobility are pneumonia and thrombosis
  • Estrogen maintains bone density in both sexes; inhibits resorption by osteoclasts
  • Postmenopausal white women are at the greatest risk; white women begin to lose bone mass as early as age 35. By age 70, their average loss is 30% of bone mass.
  • Osteoporosis also seen in young female athletes with low body fat causing them to stop ovulating and decrease estrogen secretion
  • Risk factors: race, age, gender, smoking, diabetes mellitus, diets poor which are poor in: calcium, protein, vitamins C and D
  • Treatments: Estrogen replacement therapy (ERT) (slows bone resorption, but increases risk of breast cancer, stroke, and heart disease); PTH derivative can also be used as a treatment but can cause bone cancer; certain medications destroy osteoclasts.
  • However, best treatment is prevention: exercise and a good bone-building diet between ages 25 and 40
73
Q

Describe the bone disease osteomalacia

A

Caused by low levels of calcitriol (vitamin D) in adults; leads to abnormally soft bones. This is because calcitriol is necessary for bone deposition.

74
Q

Describe the bone disease Ricket’s

A

Caused by low levels of calcitriol (vitamin D) in children; leads to abnormally soft bones. This is because calcitriol is necessary for bone deposition.

75
Q

Describe the bone disease osteogenesis imperfecta

A

A deficit in collagen deposition.

76
Q

Name and describe the types of fractures.

A
  • Non-displaced: A fracture where the bones remain aligned.
  • Displaced: A fracture where the bones become misaligned.
  • Comminuted: A fracture in which the bone breaks into several pieces
  • Greenstick: An incomplete fracture in which the bone is bent; occurs most often in children.
77
Q

Explain the ways in which a fracture can be repaired.

A
  • Closed reduction: A procedure in which bone fragments are manipulated into their normal positions without surgery
  • Open reduction: Involves surgical exposure of the bone and the use of plates, screws, or pins to realign the fragments
  • Cast: normally used to stabilize and immobilize healing bone
78
Q

Explain how the body heals fractures

A

The body repairs fractures by forming a hematoma, then a soft callus, then a hard callus, then bone remodeling.

79
Q

Predict factors or situations affecting the skeletal system that could disrupt homeostasis.

A
  • Lack of vitamin D in your diet could lead to osteomalacia, disrupting homeostasis.
  • Radiation therapy can cause damage to red bone marrow, which can lead to decreased blood cell production, which can lead to disruption of homeostasis.
80
Q

Predict the types of problems that would occur in the body if the skeletal system could not maintain homeostasis.

A

Lack of homeostatic control causes illness, injury, or death.

Anatomy and Physiology I (39 decks)

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