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Flashcards in Physiology - Exam #1 Deck (186):
1

What are the levels of Bloom's Taxonomy?

1. Creating
2. Evaluating
3. Analyzing
4. Applying
5. Understanding
6. Remembering

2

What is involved in each of Bloom's levels?

-Remembering: can the student recall or remember the information;
-Understanding: can the student explain ideas or concepts?;
-Applying: can the student use the information in a new way?;
-Analyzing: can the student distinguish between the different parts?;
-Evaluating: Can the student justify a stand or decision;
-Creating: can the student create new product or point of view?

3

What is the hierarchy of complexity within the body?

1. Cells
2. Tissues (Epithelial, Connective, Muscular, Nervous)
3. Organs
4. Organ Systems

4

What are the FOUR major types of tissues?

-Epithelial
-Connective
-Muscle
-Nervous

5

Characteristics of EPITHELIAL Tissue

-Covers organs and the body;
-Lines body cavities;
-Lines hollow organs;
-Have a FREE surface;
-Apical (free) surface either outward from the skin or in the hollow area of an organ or cavity ;
-Have a BASEMENT membrane → NONLIVING ;
-Avascular (NO blood);;
-Cells readily divide;
-Cells tightly packed;
-Cells often have desmosomes, tight junctions, or gap junctions → Side-to-side;
-Classified according to cells SHAPE and number of cell LAYERS

6

Functions of the Epithelium

-Functions in PROTECTION, SECRETIONS, ABSORPTION, and EXCRETION

7

What is the epithelial basement membrane?

The UNDERSIDE of this tissue is anchored to connective tissue by a thin, nonliving layer

8

How is Cancer spread through the basement membrane?

- By secreting a substance that dissolves basement membranes, allowing the cancer cells to invade adjacent tissue layers;
-Cancer cells also produce fewer adhesion proteins, or none at all, which allows them to invade surrounding tissues

9

What are the types of intercellular junctions?

-Tight;
-Desmosomes;
-Gap

10

Tight junctions

-Close space between cells by fusing cell membranes;
EX: Cells that line the inside of the small intestine

11

Desmosomes

-Bind cells by forming "spot welds" between cell membranes;
EX: Cells of the outer skin

12

Gap Junctions

FOrm tubular channels between cells that allow substances to be exchanged;
EX: Muscle cells of the heart and digestive tract — allow electrical conductivity

13

What are Carcinomas?

-Over 90% of human cancers are CARCINOMAS – which are outgrowths that originate in an epithelium;
-Most begin on surfaces that contact the EXTERNAL environment, such as:
oSkin
oLining of airways of the respiratory tract
oLining of the stomach or intestines
oSuggests that the more common cancer-causing agents may not penetrate tissues very deeply

14

What is the Glandular Epithelium?

-Composed of cells that are specialized to produce and secrete substances into ducts or into body fluids;
-Such cells are usually found within columnar or cuboidal epithelium, and one or more of these cells constitutes a GLAND

15

EXOCRINE Glands

-Glands that secrete their products into ducts that open onto some internal or external SURFACE;
-EXOCRINE gland may consist of a SINGLE epithelial cell (unicellular gland → ex. Goblet cells), or it may be composed of many cells (multicellular gland)

16

ENDOCRINE Glands

Glands that secrete their products into INTERSTITIAL FLUID or BLOOD

17

What are theTWO types of Multicellular Glands?

-SIMPLE gland communicates with the surface by means of an unbranched duct;
-COMPOUND gland has a branched duct

18

Tubular Glands

Glands that consist of epithelial-lines tubes

19

Alveolar (acinar) glands

Glands whose terminal portions form saclike dilations → Bubble-like end

20

What are most EXOCRINE Secretory Cells?

-MEROCRINE, and they can be further subdivided:
1. Serous cells = secretion is typically watery, has a high concentration of enzymes, and is called serous fluid → Common in the linings of body cavities;
2. Mucus Cells = secrete a thicker fluid mucus; this substance is rich in the glycoprotein mucin and is abundantly secreted from the inner linings of the digestive and respiratory systems

21

What are the Methods of Glandular Secretion?

1. Merocrine;
2. Apocrine;
3. Holocrine

22

Merocrine Glands

-Secretion is a FLUID PRODUCT released through the cell membrane by exocytosis;
Ex. – Salivary glands, pancreatic glands, sweat glands of the skin

23

Apocrine Glands

-CELLULAR PRODUCT and portions of the free ends of glandular cells pinch off during secretion;
Ex. - Mammary glands, ceruminous glands lining the external ear canal (secrete ear wax)

24

Holocrine Glands

-Entire cells laden with SECRETORY PRODUCTS disintegrate;
Ex. – Sebaceous glands of the skin

25

Characteristics of CONNECTIVE Tissue

-Most abundant tissue by weight;
-Further apart that epithelial cells;
-Lots of intercellular material (MATRIX) between;
-Cells usually divide;
-Varying degrees of vascularity;
-Bone/cartilage are rigid;
-Loose connective tissue (areolar), adipose tissue, and dense connective tissue are more variable

26

What are the major Connective Tissue cell types?

1. FIXED cells are usually present in stable numbers;
2. WANDERING cells temporarily appear in tissues, usually in response to an injury or infection

27

Types of FIXED cells

1. Fibroblast – the most common kind of fixed cell in connective tissue; it produces fibers by secreting protein into the matrix of connective tissue;
2. Mast cell – are large and widely distributed in connective tissue, where they are usually located near blood vessels

28

What is released by Mast Cells?

-Heparin – a compound that prevents blood clotting;
-Histamine – a substance that promotes some of the reactions associated with inflammation and allergies, such as asthma and hay fever

29

Types of Wandering Cells

-Macrophages – or histocytes originate as white blood cells and are almost as numerous as fibroblasts in connective tissue;
-Usually attached to fibers but can detach and actively move about. They function as scavenger cells that can clear foreign particles from tissues making them an important defense against infection;
-Also play a role in immunity → Transfer antigens!

30

What is Histamine?

-Release of histamine stimulates INFLAMMATION by dilating the small arterioles that feed capillaries;
-Resulting SWELLING and REDNESS is inhospitable to infectious bacteria and viruses and also dilutes toxins;
-INAPPROPRIATE histamine release as part of an allergic response can be most uncomfortable;
-Allergy medications called ANTIHISTAMINES counter this misplaced inflammation

31

What are the types of fibers produced by FIBROBLASTS (fixed connective)?

1. Collagenous fibers;
2. Elastic fibers;
-3. Reticular Fibers

32

Collagenous Fibers (Connective)

-Abundant – thick threads of the protein collagen (major structural protein);
-Grouped into long, parallel bundles, and they are flexible but only slightly elastic → Bend, DO NOT STRETCH;
-Great tensile strength; they can resist considerable pulling force;
-Important components of body parts that hold structures together, such as ligaments and tendons
-Ligaments – connectives bones to joints;
-Tendons – form a sheath around the bone to connect them to the joint

33

What are the varying amounts of Collagenous fibers?

-Tissue containing ABUNDANT collagenous fibers is called DENSE connective tissue; is it white and sometimes called white fibers;
-LOOSE connective tissue, on the other hand, has SPARSE collagenous fibers

34

How does Connective Tissue change over time?

-When skin is exposed to prolonged and intense sunlight, connective tissue fibers lose elasticity, and the skin stiffens and becomes leathery;
-In time, the skin may sag and wrinkle;
-Collagen injections may temporarily smooth out wrinkles;
-However, collagen applied as a cream to the skin does not combat wrinkles because collagen molecules are far too large to actually penetrate the skin

35

Elastic Fibers (Connective)

-Abundant – are composed of bundles of microfibrils embedded in a protein called ELASTIN;
-Fibers branch, forming complex networks in various tissues;
-WEAKER than collagenous fibers but very elastic;
-Elastic fibers are common in body parts that are normally subjected to stretching, such as the vocal cords and air passages of the respiratory system;
-Elastic fibers are sometimes called YELLOW FIBERS, because tissues amply supplied with them appear yellowish

36

What is ELASTIN (from elastic fibers)?

-Elastin is used in foam, powder, or sheet form to prevent scar tissue adhesions from forming at the sites of tissue removal;
-Elastin is produced in BACTERIA that are genetically altered to contain human genes that instruct them to manufacture it — Cheaper than synthesizing elastin chemically and safer than obtaining it from cadavers

37

Reticular Fibers (Connective)

-Very thin collagenous fibers;
-Highly BRANCHED and form delicate supporting networks in a variety of tissues

38

What are the types of Connective TISSUES?

1. Connective Tissue PROPER ;
2. SPECIALIZED Connective Tissue

39

Connective Tissue PROPER

1. Loose connective tissue;
2. adipose tissue;
3. reticular connective tissu3;
4. Dense connective tissue;
5. Elastic connective tissue

40

SPECIALIZED Connective Tissue

1. cartilage;
2. bone;
3. blood

41

Loose Connective Tissue
(Connective Proper)

-Loose Connective or areolar tissue forms delicate, thin membranes throughout the body;
-Fibroblasts are located some distance apart and are separated by a gel-like ground substance that contains many collagenous and elastic fibers that fibroblasts secrete;
-Loose connective tissue binds the skin to the underlying organs and fills spaces between underlying muscles;
-Beneath most layers of epithelium, where its many blood vessels nourish nearby epithelial cells

42

Adipose Connective Tissue
(Connective Proper)

-Fat;
-Adipocytes – certain cells within connective tissue, store fat droplets in their cytoplasm;
-At first, these cells resemble fibroblasts, but as they accumulate fat, they enlarge, and their nuclei are pushed to one side;
-A lot of adipocytes crowd out other cell types and form adipose tissue;
-Born with a certain number of fat cells;
-Amount of adipose tissue in the body reflects DIET or an ENDOCRINE DISORDER

43

What are the functions of Adipose?

-Lies beneath the skin, in spaces between muscles, around the kidneys, behind the eyeballs, in certain abdominal membranes, on the surface of the heart, and around certain joints;
-Cushions certain joints and some organs such as the kidneys;
-Insulates beneath the skin, and it stores energy in fat molecules

44

Bone
(Specialized Connective)

-Bone is the most RIGID connective tissue;
-Hardness is largely due to mineral salts, such as calcium phosphate and calcium carbonate, in its matrix;
-Intercellular material also contains a great amount of collagen, whose fibers flexibly reinforce the mineral components of bone;
-Bone internally supports body structures;
-Contains red marrow, which forms blood cells, and it stores and releases inorganic salts

45

What is the structure of the Bone MATRIX?

-Supported by bone cells, OSTEOCYTES, in thin layers called LAMALLAE, which form concentric patterns around capillaries located within tiny;
--Osteocytes are located in LACUNAE (cavities) that are rather evenly spaced between the lamellae

46

What is an OSTEON?

In a bone, the osteocytes and layers of intercellular material, which is concentrically clustered around a central canal, form a cylinder-shaped unit called an OSTEON, or Haversian System;
**Osteon = Osteocyte + Layers

47

How are nutrients supplied throughout the bone?

-Each central canal contains a blood vessel, so every bone cell is fairly close to a nutrient supply;
-Osteocytes have many cytoplasmic processes that extend outward and pass through minute tubes in the matrix called CANALICULI;
-Gap junctions attach these cellular processes to the membranes of nearby cells;
-Injured bone heals more rapidly than injured cartilage because of the proximity of blood vessels and osteocytes → Closer to nutrients in blood causing quicker healing

48

Cartilage
(Specialized Connective)

RIGID connective tissue:;
-Provides support, frameworks, attachments, protects underlying tissues, and forms structural models for many developing bones;
-Cartilage matrix is abundant and largely composed of collagenous fibers embedded in a gel-like ground substance

49

What is the ground substance of the Collagen Matrix?

-The ground substance is rich in a protein-polysaccharide complex (chondromucoprotein) and contains a large amount of water;
-Cartilage cells, or chondrocytes, occupy small chambers called lacunae and thus lie completely within the matrix

50

What is the Perichondrium?

-A cartilaginous structure is enclosed in a covering of connective tissue = Perichondrium;

51

What are the THREE types of Cartilage?

1. Hyaline;
2. Elastic;
3. FIbrocartilage

52

Hyaline Cartilage

-Most common type, looks somewhat like white glass;
-Found on the ends of bones in many joints, in the soft part of the nose, and in the supporting rings of the respiratory passages

53

Elastic Cartilage

-More flexible than hyaline cartilage because its matrix contains many elastic fibers;
-Provides the framework for the external ears and parts of the larynx.

54

Fibrocartilage

-Very tough tissue, contains many collagenous fibers;
-Shock absorber for structures that are subjected to pressure;
-Fibrocartilage forms pads (intervertebral discs) between the individual bones (vertebrae) of the spinal column;
-Intervertebral discs shrink as people age → Loss of height ;
-Also cushions bones in the knees and in the pelvic girdle

55

Blood
(Specialized Connective)

-Blood is composed of cells that are suspended in a fluid intercellular matrix called PLASMA;
-These cells include:
1. Red blood cells = Erythrocytes
2. White Blood Cells = Leukocytes3. Blood platelets = Thrombocytes = cellular fragments

56

Where are blood cells made and function?

-Most blood cells form in special tissue = Hematopoietic tissue;
-In RED marrow within the HOLLOW parts of certain bones;
-Red marrow is found in almost all bones of a baby, but disappears from bones of the body with age ;
-ONLY the red blood cells function entirely within the blood vessels;
-White blood cells typically move from the blood through capillary walls;
-Platelets leave the blood vessels when they are damaged

57

Characteristics of MUSCLE Tissue

-Due to their elongated shape, the cells in muscle tissues are called muscle fibers → Fibers are composed of MYOSIN and ACTIN;
-Fibers are CONTRACTILE, they can shorten and thicken;
-As they contract, muscle cells pull at their attached ends, which move body parts;
-THREE types of muscle tissue
1. Skeletal = striated = voluntary
2. Smooth = involuntary;
3. Cardiac) = striated = involuntary

58

Skeletal Muscle Tissue

-Muscles that usually attach to bones and they are controlled by conscious effort;
-90% of muscle mass;
-LONG – up to > 40 mm in length – and narrow - < 0.1 mm in width;
-Alternating light and dark cross- markings called STRIATIONS
-Multinucleated ( many nuclei) → ONLY CELLS that are MULTINUCLEATED

59

How do Skeletal Muscles move?

-A message from a nerve cell can stimulate a muscle cell to contract by causing protein filaments within the muscle cell to slide past each other → Sliding Filament Hypothesis ;
-Skeletal muscles move the head, trunk, and limbs and enable us to make facial expressions, write, talk, and sing, as well as chew, swallow, and breath

60

Smooth Muscle Tissue

-Lacks striations;
-Shorter than those of skeletal muscle and are spindle-shaped, each with a single, centrally located nucleus;
-NOT STRIATED with a ratio of actin to myosin of 16:1 → NOT the 2:1 of smooth abd cardiac striated muscle;
-Actin is connected to dense bodes;
-Comprises the walls of hollow internal organs, such as the stomach, intestines, urinary bladder, uterus, and blood vessels;
-NOT stimulated to contract by conscious effort; actions are INVOLUNTARY;
Ex., smooth muscle tissue moves food through the digestive tract (peristalsis), constricts blood vessels (vasoconstriction), and empties the urinary bladder

61

Cardiac Muscle Tissue

ONLY in the heart;
-Striated cells joined end-to-end;
-Branched and interconnected in complex networks;
-SINGLE NUCLEUS;;
-Where one cell touches another cell is a specialized intercellular junction, called an INTERCALATED DISC (gap junctions), seen in cardiac muscle and single motor unit smooth muscle
- Involuntary and can continue to function without being stimulated by nerve impulses (AUTOMOTICITY)

62

How do muscle cells divide?

-Vary greatly in their abilities to divide. ;
-SKELETAL and CARDIAC muscle cells and NERVE cells (neurons) DO NOT usually divide at all after differentiating;
-Fibroblasts respond rapidly to injuries by increasing in number and fiber production

63

How do Fibroblasts repair injuries?

-They are often the principal agents of repair in tissues that have limited abilities to regenerate;
-For instance, cardiac muscle tissue, typically degenerates in the regions damaged by a heart attack;
-Fibroblasts then, over time, knit connective tissue that replaces the damaged cardiac muscle;
-A scar is formed

64

Nervous Tissue

-Found in the brain and spinal cord;
-Basic cells are neurons;
-Neurological cells are supporting cells;
-Sensory reception;
-Conduction of nerve impulses;
-Cell types = Neurons, Glial Cells, and Sensory Receptors

65

What are Neurons?

conduct action potentials

66

What are Glial Cells?

Support Cells =
-Schwann cells;
-Oligodendrocytes
-Satellite cells;
-Astrocytes;
-Microglia;
-Ependyma

67

Schwann Cells

-Myelin sheaths around PERIPHERAL axons

68

Oligodendrocytes

-Shaped like astrocytes but with fewer cellular processed and occur in rows along axons;
-Myelin sheaths around CNS axons;
-Produce nerve growth factors

69

Satellite cells

ganglionic gliocytes

70

Astrocytes

-Star-shaped cells between neurons and blood vessels;
-Regulate passage of molecules from the blood to the brain;
-Structural, form scar tissue, transports between vessels and neurons;
-Communication between each other and neurons;
-Pick up excess ions and neurotransmitter;
-Induce synapses

71

Microglial cells

-Small cells with few cellular processes and found throughout the CNS:
-Phagocytic ameboid cells in CNS (immunity)

72

Ependyma

-Cuboidal and columnar cells in the inner lining of the ventricles of the brain and central canal of the spinal cord;
-Cover tufts of capillaries to form the choroid plexus;
-Form a porous layer for substances to diffuse between interstitial fluid of the brain and spinal cord and cerebrospinal fluid

73

What is Homeostasis?

-The maintenance of extracellular fluid under constant conditions;
-Most control systems function on the basis of negative feedback control

74

Set Point Body Temp

Normally, the temperature of deeper body parts remains close to a SET POINT of 37oC (98.6oF) → Can be variation around the set point from person to person

75

What is Heat?

-Byproduct of cellular metabolism;
-Respiration is about 2/3 efficient, remaining energy found in the bonds of glucose that are released upon breakdown are released as HEAT;
-Inefficient mitochondria release the heat making us Endotherms and maintain a set body temp

76

What are the means of Body Heat LOSS?

1. Radiation;
2. Conduction;
3. Convection;
4. Evaporation
*Conduction and Convection release LESS heat

77

Radiation

primary means – infrared heat rays escape from warmer surfaces to cooler surroundings

78

Conduction

heat moves from the body directly into the molecules of cooler objects in contact with its surface (solids and liquids)

79

Convection

continuous circulation of air over a warm surface (body)

80

Evaporation

conversion of sweat from a liquid to a gaseous phase carries heat away from the surface, cooling the skin; high relative humidity of water vapor retards evaporative cooling; athletes are advised to slow down their activities on hot, humid days

81

Nonshivering Thermogenesis

-If the body temperature continues to drop, the nervous system may stimulate muscle cells in the skeletal muscles throughout the body to contract slightly;
-Requires an increase in the rate of cellular respiration and release of heat as a byproduct

82

Shivering Thermogenesis

If non shivering response does not raise the body temperature to normal, small groups of muscles may contract rhythmically with still greater force, causing the person to shiver

83

Hyperthermia

RISE in body temperature above normal;
-Causes = environmental, exercise, and fever;
-High RH – sweat can’t evaporate quickly

84

Hypothermia

-LOWERED body temp can result from prolonged exposure to coldness or illness;
-Begins with shivering, and a feeling of coldness, but if not treated progresses to mental confusion, lethargy, loss of reflexes and consciousness, and even the shutting down of major organs;
-If the temperature of the body core DROPS just a few degrees, fatal respiratory failure or heart arrhythmia may result

85

Who is more at risk for Hypothermia?

-Very young
-Very old
-Very thin
-Homeless

86

When is Hypothermia done on purpose?

-Intentionally induced during certain surgical procedures involving the heart or central nervous system; pack patient in ice or remove blood, cool it, and return it to the body;
-Heart surgery – body temperature is cooled to 26 – 32oC

87

What is an Organ?

a structure in the body composed of two or more primary tissues that performs a specific function

88

What is an Organ System?

a number of organs functioning together in an integrated fashion

89

Characteristics of the SKIN and INTEGUMENTARY System

-Composed of several tissues;
-Maintains homeostasis;
-Protective covering;
-Retards water loss;
-Regulates body temperature;
-Houses sensory receptors → Touch, heat, etc;
-Contains immune system cells;
-Synthesizes chemicals;
-Excretes small amounts of waste → Primarily urea (protein metabolism)

90

Layers of the skin

1. Epidermis (distinct)
2. Dermis (distinct)
3. Subcutaneous layer

91

Epidermis Skin Layer

-OUTER = composed of stratified squamous epithelium;
-Basement membrane = anchored to the dermis by short fibrils separates the two skin layers

92

Dermis Skin Layer

-INNER = thicker than the epidermis and is made up of connective tissue containing collagen and elastic fibers, epithelial tissue, smooth muscle tissue, nervous tissue, and blood;
-Contains the capillaries and veins of the Rete Cutanuem

93

Subcutaneous Skin Layer

-Somewhat diffuse, not as distinct);
-Located BENEATH the DERMIS → masses of loose connective and adipose tissues that bind the skin to underlying organs

94

Characteristics of the EPIDERMIS Layer

-LACKS blood vessels
-Keratinized
-Thicket on PALMS and SOLES (0.8-1.4mm)
-Melanocytes provide melanin;
-Rests on basement membrane ;
-Stratified squamous

95

Melanocytes

Specialized cells that are the ONLY ones that produce protective pigment Melanin; Have fingerlike process that secrete the melain pigment into nearby squamous cells and take on that pigment

96

Layers of the Epidermis

1. stratum corneum – many layers of tough, tightly packed and keratinized dead cells – eventually shed
2. stratum lucidum – additional thickened skin layer of the palms and soles
3. stratum granulosum - a granular layer
4. stratum spinosum – a thick layer
5. stratum basale – deepest layer; nourished by dermal blood vessels so the cells can divide and grow → Innermost layer and ONLY one that undergoes MITOTIC DIVISION

97

Calluses

Growth of thickened areas where skin is rubbed pr pressed regularly due to increased rate of cell division

98

Corns

keratinized conical masses on the toes created from the increased rate of cell division from repeated rubbing and pressing of skin

99

Melanin

-dark pigment melanin that provides skin color produced by melanocytes;.
-Melanin absorbs ultraviolet radiation in sunlight, preventing mutations in the DNA of skin cells and other damaging effects

100

Solar Erythema

Acute Sunburn;
-–an INFLAMMATORY reaction of the skin to excessive exposure to UV radiation in sunlight;
-Treatment for acute sunburn – frequent cool baths with oatmeal or baking soda added to soothe;
-To AVOID sunburn, stay out of the sun from 10AM to 3PM and apply sunblock of at least SPF 15, even on a cloudy day;
-Tanning lotions, reflectors, sunlamps, or tanning booths may pose a risk of sunburn

101

What is Apoptosis?

-Programmed cell death;
EX: Peeling → PREVENTS CANCER from developing after a sunburn

102

What happens as the skin is exposed to more and more sun?

-Continued sun exposure leads to tanning, as specialized skin cells produce MORE melanin pigment;
-At the same time, the STRATUM CORNEUM thickens;
-Over time, sun overexposure hastens wrinkling and may produce a leathery feel as the skin loses elasticity

103

How does Sun Exposure effect the skin cells?

-Melanocytes lie in the DEEPEST portion of the epidermis, and in the surrounding connective tissue of the dermis;
-ONLY melanocytes can produce melanin but the pigment may also be present in nearby epidermal cells because melanocytes have long, pigment-containing cellular extensions that pass upward between neighboring epidermal cells;
-Melanin granules are transferred into other cells by CYTOCRINE SECRETION;
-Nearby neighboring cells may contain more melanin than the melanocytes = STORE it;
-One consequence of excessive sun exposure is SKIN CANCER

104

How does Skin Cancer occur?

-Begins when UV radiation causes mutation in the DNA of a skin cell;
-People who inherit the very rare condition XERODERMA PIGMENTOSUM are very prone to developing skin cancer because they lack DNA repair enzymes → CANNOT FIX damaged DNA;
-Most skin cancer occurs in NONpigmented epithelial cells;
-Can sometimes occur in melanocytes

105

What are Cutaneous Carcinomas?

-Skin cancer usually arises from NONPIGMENTED epithelial cells within the deep layer of the epidermis or from pigmented melanocytes;
-Skin cancers originating from epithelial cells are called CUTANEOUS CARCINOMAS (basal cell carcinoma or squamous cell carcinoma);
**Most common type of skin cancer – slow growing and can usually be cured;
-Often develops from a hard, dry, scaly growth with a reddish base

106

What are Cutaneous Melanomas?

-Skin cancers originating from melanocytes are CUTANEOUS MELANOMAS;
-Pigmented with melanin, often with a variety of colored areas – variegated brown, black, gray, or blue;
-Light skinned people who burn not tan;
-People of any age;
-Caused by short, intermittent exposure to high intensity sunlight ;
-Surgical removal during the horizontal growth phase can stop;
-Once the lesion thickens and spreads into deeper tissues, it becomes more difficult to treat, and the survival rate is very low

107

Characteristics of the DERMIS Layer

-On average 1.0-2.0mm thick ;
-Dermal papillae;
-Binds epidermis to underlying tissues;
-Irregular dense connective tissue;
-Muscle cells;
-Nerve cell processes;
-Blood vessels;
-Hair follicles;
-Glands

108

What are the Conical papillae of the Dermis?

-Projections from the dermis that pass into the spaces of the inwards ridges of the epidermis;
-Forms the uneven boundary between the epidermis and dermis;
-Fingerprints form from these undulations of the skin at the distal end of the palmer surface of the finger (genetically determined)

109

Thickness of the Dermis layer

On average the dermis is:
-1.0 -2.0 mm thick
-0.5 mm or less on the eyelids
-3.0 mm on soles of feet

110

What is the Dermis layer composed of?

-Composed of irregular dense connective tissue that includes collagenous fibers and elastic fibers in a gel-like ground substance;
-Muscle fibers;
-Nerves cells;
**Blood vessels, hair follicles, sebaceous glands, sweat glands

111

Muscle Fibers of the Dermis

-Scrotum – smooth muscle wrinkle the skin when contract;
-Associated with accessory organs such as hair follicles and glands;
-Many skeletal muscle fibers are anchored to the dermis in the skin of the face

112

Nerves Cell Processes of the Dermis

-Scattered throughout the dermis – sensory receptors;
-Pacinian corpuscles –heavy pressure;
-Meissner’s corpuscles – light touch;
-Temperature changes;
-Tissue damage

113

Characteristics of the Subcutaneous Layer

-Hypodermis;
-Loose connective tissue;
-Adipose tissue = Insulates by conservation and preventing the entrance of heat;
-Major blood vessels supply skin;
-Vessel branches form a network (RETE CUTANEUM) between dermis subcutaneous layer

114

What are the Accessory Organs of the Skin?

-Hair follicles;
-Nails;
-Skin glands = Sebaceous glands and Sweat glands;
(Sweat glands = Eccrine glands and Apocrine glands)

115

What is a Hair Follicle?

-Each hair develops from a group of epidermal cells at the base of a TUBELIKE DEPRESSION called a hair follicle;
-Each hair follicle also has associated with it one or more SEBACEOUS (oil-producing) glands

116

What is a Hair Root?

-The portion of hair embedded in the skin;
-The follicle extends from the surface into the dermis and contains the hair root

117

What is a Hair Papilla?

-Projection of connective tissue (hair papilla) at the deep end of the follicle that nourishes epidermal cells are the base of the follicle through dermal blood vessels;
-Where mitotic division takes place and gives rise to the hair

118

What is the Hair Shaft?

Remains of the keratinized and dead epidermal cells that extend away from the skin forming a hair

119

What are the differences in hair color?

**Genes determine hair color by directing the type and amount of pigment that epidermal melanocytes produce
1. Dark hair –much more melanin than blond hair;
2. White hair with the inherited condition albinism lacks melanin;
3. Bright RED hair contains the IRON PIGMENT TRICHOSIDERIN that is not in hair of any other color

120

What is the Arretor Pili Muscle?

A bundle of SMOOTH MUSCLE CELLS attaches to each hair follicle → if a person is upset or cold, nerve impulses may stimulate this muscle to contract, raising goose bumps

121

What is Folliculitis?

-INFLAMMATION of the hair follicles in response to bacterial infection;
-More common in MEN where it is associated with SHAVING;
-Woman – repeatedly using a loofah sponge containing bacteria

122

What are the Inherited Hair Characteristics?

-Cowlick – direction; clockwise swirl is more common;
-White forelock;
-Hairy ears, elbows, nose tip, or palms

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How do hairs grow?

-A hair typically grows for TWO to SIX YEARS, rests for two to three months, then FALLS OUT;
-A new hair grows in its place;
-At any time, 90% of hair is in the growth phase;
-Sometimes may not be replied leading to baldness (57.5 million in the US)

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What is Pattern Baldness?

**Top of the head loses hair, affects =
-35 million MEN – associated with testosterone – androgenic alopecia;
-20 million WOMEN – past menopause – lowered estrogen;
-Alopecia areata – 2.5 million people – inherited – AUTOIMMUNE

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What causes TEMP hair loss?

-Lowered estrogen levels shortly before and after birth;
-Birth control pills, cough medications, certain antibiotics, vitamin A derivatives, antidepressants;
-Sustained high fever

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How is hair loss treated?

1. Minoxidil (Rogaine) – causes new hair to grow in 10-14% of cases but it slows hair loss in 90% of cases; stop taking it and any new hair falls out;
2. Hair transplants move hair follicles from a hairy part of a person’s bodyto a bald part – successful;
3. Potentially damaging to the scalp = Suturing on hair pieces;
4. Thinning hair supplements are merely conditioners → merely make hair FEEL thicker

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Components of a Hair Follicle?

-Epidermal cells;
-Tube-like depression;
-Extends into dermis;
-Hair root → portion of the hair embedded into the skin;
-Hair shaft → Extends away from the surface of the skin;
-Hair papilla → Projection of connective tissue containing dermal blood vessels at the deep end of the follicle that help nourish the base epidermal cells ;
-Dead epidermal cells → Outer layer is dead creating a protective, waterproof coating ;
-Melanin → Protective pigment ;
-Arrector pili muscle → bundle of smooth muscles attached to the hair follicle; can contract causing goose bumps

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What are Nails?

-Protective coverings on the ends of fingers and toes;
-Each nail consists of a NAIL PLATE that overlies a surface of skin called the NAIL BED;
-Specialized epithelial cells that are continuous with the epithelium of the skin produce the nail bed

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What is the Lunula of the Nail?

-The whitish, thickened, half moon-shaped region (lunula) at the base of the nail plate is the most active growing region;
-The epithelial cells here DIVIDE, and the newly formed cells are KERATINIZED;
-Gives rise to tiny keratinized scales that become part of the nail plate, pushing forward over the nail bed;
-In time, the plate extends beyond the nail bed and with normal use gradually wears away

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Bluish Nails

may reflect a circulation problem

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White Nail bed or Oval Depressions in a nail

may indicate anemia

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Horizontal Furrows of the Nail

may result from a period of serious illness or may indicate malnutrition

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Extreme Curvature of the nails

Certain disorders of the lungs, heart, or liver

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Red Streaks in Non-Injured Nails

may be traced to rheumatoid arthritis, ulcers, or hypertension

135

What is the Cell Protoplasm?

The different substances that make up the cell fluid :
-Water – HOH → About 92%
-Electrolytes – Na+, Cl-, Ca++, etc. → Charged
- Biochemical Substrates=
oProteins – amino acids
oLipids – Neutral fats, sterols, phospholipids
oCarbohydrates – monosaccharides
oNucleic acids- phosphate group, pentose sugar, nitrogen base

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What is the Cell Membrane?

-Described by the Fluid Mosaic Model (Singer and Nicholson);
-Line all physical stuctures;
-Mostly lipids and proteins;
EX: Cell, nuclear, mitochondrial, ER, and Golgi have membranes

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What is the Lipid BIilayer of Cell Membranes?

-Thin film of lipids 2 molecules thick;
-Contains large globular proteins;
-Impermeable to water and water-solubles;
-Fat-soluble are permeable (O2, CO2, alcohol, steroids);
-Lipid FLUID, not solid

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What are the types of membrane proteins?

-Most are Glycoproteins (carb attached);
-Integral and Peripheral Protains

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Integral Proteins

Penetrate THOUGH the membrane;
Path for water and ions to pass

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Peripheral Proteins

Attached to the SURFACE of the membrane;
-Almost always attached to an integral protein;
-Mostly enzymatic function

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What the Cell Membrane Carbohydrates?

-Occur in combo with proteins (glycoproteins) and lipids (glycoplipids);
-Entire surface of cells usually has loose carb covering = Glycocalyx

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What are the functions of the Glycocalyx?

-Carry a net negative charge - repels other charges;
-Some adjacent cells attached - desmosomes;
-Receptors for binding hormones (insulin and other peptides);
-Some immune reactions (antigenic)

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What is the Cytosol?

Clear fluid of the cytoplasm;
-Contains proteins, electrolytes, glucose., phospholipids, cholesterol and esterified fatty acids

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What are the dispersed particles found in the cytoplasm?

-Neutral fats;
-Glycogen granules;
-RIbosomes;
-Secretory granules

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What percent of the world is under or malnourished?

20-60%

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Ingestion

Taking food in by mouth

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Digestion

simplification of food by chemical and physical means into smaller molecules for the absorption of materials

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Absorption

movement of simplified food molecules from the lumen of the GI tract into the blood and lymph

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Transportation

Sytem of carrying food from the site of digestion and absorption to the cells of the body per FUSION

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Assimilation

incorporation of food into protoplasm of the cell (either stored or used for energy);
Much of the food ingested is stored for a period of time

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Excretion

Voiding of metabolic waste through the skin, lungs, intestines, and kidneys

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Egestion

Food products that are NOT absorbed but are passed on by the GI tract and EGESTED as feces

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What is the role of the digestive tract

-Ingest, digest and absorb food into the blood and lymph for transport around the body;
-Almost entirely extracellular;
-Long tube from mouth to anus that is compartmentalized anatomically and functionally

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What makes up the Digestive System?

Mouth;
Pharynx;
Esophagus;
Stomach (duodenum, jéjunum, ileum);
LI;
Rectum;
Anus

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What 3 organs or sets of glands help digestion?

1. Salivary Glands = Sublingual, Submandibular, Paratoid;
2. Liver
3. Pancreas = several digestive and intestinal enzymes

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What is the anatomical composition of the Alimentary Tract (GI tract) from OUT to IN

1. Out = Serosa;
2. Muscle layer = smooth;
3. Submucosa
4. Very inner = Mucosa

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What increases the area of the SI?

1. Folded intestinal mucosa — Plicae circulares (large circular folds all the way around) = 3x;
2. Villi — 1mm above mucosal surface by the millions = 10x
3. Brush border microvilli — 20x
Total = 3x10x20 = 600 times increases = 250 sq. meters of SI

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Digestion in the MOUTH

1. Teeth reduce food size;
2. Saliva mixed
3. Bolus or ball formed
4. Tongue pushes bolus and liquids to pharynx
5. HYPOPHARYNGEAL SPHINCTER contracts
6. Saliva secreted by salivary gland

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Functions of Saliva in the Body

1. Helps form bolus for swallowing
2. Contains alpha-amylase enzyme (ptyalin)
3. Helps taste
4. Cleans mouth/teeth
5. Contains lysozyme with digests bacterial walls
6. Excretory medium for I, Hg, Pb, thiocynate, urea and some other organic subs
**1000-1500mL of saliva per day

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Functions of Amylase

1. Breaks down starch — dextrins — maltose (disacch)
2. Most activity only takes place in first 15-30 mins
3. Inactivated in the stomach by low pH (2-3) = denatured

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Sublingual Gland (salivary)

duct opens below the anterior portion of tongue via duct of Barthalia

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Submandibular Gland (salivary)

posterior to sublingual; below the anterior part of the tongue;
Whartons duct

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Parotid Gland (salivary)

angle of the jaw = front of ear;
-Stensons duct;
-orfice opposite the crown of the second upper molar

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What types of cells secrete saliva?

Mucous = mucous
Serous = alpha-amylase
*Secretion under autonomic nervous control

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How does food move down the first part of digestion?

Bolus
-Pharynx
-Esophagus
-Stomach
**By PERISTALTIC contraction of smooth muscles

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Cardiac Sphincter

Separates ESOPHAGUS from STOMACH

167

Pyloric Sphincter

Separates STOMACH from DUODENUM

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What are the glands of the stomach?

Oxyntic = Gastric Glands;
6 cells :
1. Goblet (mucous neck) = secrete mucin
2 Chief (peptic cells) = secrete pepsinogen
3. Parietal cells = HCL and intrinsic factor
4. Enterochromaffin-like cells = secrete Histamine and Serotonin as paracrine regulators
5. G cells = secrete Gastrin to blood
6. D cells = secrete somatostatin to blood

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Gastrin

HORMONE that releases products of gastric glands

170

Somatostatin

Inhibits gastric motility

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Pepsin

Active form of Pepsinogen;
Breaks down proteins — proteoases — peptones (but NOT AAs)
**Pepsinogen + HCl = Pepsin + Fragment

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Functions of HCl

Stomach pH = 2-3;
1. Activate pepsinogen to pepsin
2. Denatures proteins
3. Makes gastric juice antiseptic
4. Initiates conversion of cane sugar

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Gastric Lipase

-Breaks complex fats down to 3 fatty acids + glycerol

174

Chyme

Partially liquified foodstuff through the action of digestive enzymes and HCl

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Gastric Inhibitory Peptide (GIP)

Released in response to a lot of fats and carbs entering into the duodenum to SLOW the gastric motility and the release of food into the small intestine

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Gastric Ulcers

-Caused by bacterium H. pylori

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How does food move from stomach to small intestine?

-Food at pyloric region of the stomach;
-Enters duodenums (basic pH, 25 cm long) at PYLORIC SPHINCTER;
-Pancreatic + BIle Ducts enter the duodenum about 10cm past sphincter

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Pancreas

-Behind the stomach;
-12-15 cm;
-Main duct extends the entire length with many tributaries;
-PANCREATIC DUCT + COMMON BILE DUCT join to enter the duodenum at an orfice called the Duodenal Papilla

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Major Pancreatic Enzymes

1. Trypsin (tryptase) = proteolytic enzyme (inactive as trypsinogen)
2. Chymotrypsin = proteins to proteoses
3. Peptidases = peptides to AAs
4. Amylase = acts on starch
5. Lipase = acts on fats
6. RNAase = RNA to nucleotides
7. DNAase = DNA to nucleotides
8. Bicarbonate enzymes (HCO3) — sodium bicarbonate to neutralize gastric juices in SI

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What controls pancreatic secretions?

1. Autonomic nervous;
2. Hormones
-Secretin = releases of HCO3 (bicarb ions)
-CCK (pancreozymin) = stimulates flow of pancreatic fluid

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Islets of Langerhans

Found in the pancreas;
-Secrete 2 hormone involved in blood sugar regualtion;
1. Alpha cells = GLUCAGON — glycogenolysis to raise
2. Beta cells = INSULIN — glycogenesis to lower by increasing facilitated diffusion of glucose into cells

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Liver

-Largest organ;
1. Secretes bile (GB stores)
2. Glycogenic function — glucose
3. Protein and fat metabolism
4. Site of synthesis of plasma albumin, globulin, fibrinogen, and heparin

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Gallbladder

-Green sac undersurface of the liver;
-Hold 30mL of bile and drains it to the common bile duct that receives the hepatic duct from the liver;
-Control over the release of Bile is nervous and hormonal — hormones most important = CCK causes contraction

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Bile Components

1. Bile Pigments = Breakdown products of Hb catabolism = bilirubin
2. Bile Acids = cholic acid and chenodeoxycholic acid — emulsify fats (act as detergents)
3. Cholesterol = sterol needed for steroid hormones (too much causes gall stones)
4. Mucin

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Small Intestine

-3 sections = duodenum, jéjunum, ileum;
-Glands = Brunner’s Gland;
-Brush border enzyme perform the final breakdown of food

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SI Brush Border Enzymes

1. Maltase, sucrase, lactase
2. Enterokinase
3. Peptidases
4. Lipases
5. Nucleosidases — intracellular in submucosa