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Exocrine Glands Exocrine glands – “externally secreting” - secrete their products onto body surfaces (skin) or into body cavities Examples include mucous,

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Presentation on theme: "Exocrine Glands Exocrine glands – “externally secreting” - secrete their products onto body surfaces (skin) or into body cavities Examples include mucous,"— Presentation transcript:

1 Exocrine Glands Exocrine glands – “externally secreting” - secrete their products onto body surfaces (skin) or into body cavities Examples include mucous, sweat, oil, & salivary glands Almost all exocrine glands are multicellular. Are more numerous than endocrine glands Are classified according to duct type & structure of their secretory units

2 Functions of Connective Tissue Functions of Connective tissue – 1- Binding & support – 2 - Protection – 3 - Insulation – 4 - Transportation

3 Characteristics of Connective Tissue Characteristics of connective tissues – 1 – All connective tissues arise from mesenchyme – (an embryonic tissue) so they all have a common tissue of origin – 2 – Connective tissue has varying degrees of vascularity (amounts of blood vessels running through them) ex: cartilage has few blood vessels, bone has more – 3 - Nonliving extracellular matrix, consisting of ground substance and fibers

4 Characteristics of Connective Tissue – 3 – Connective tissue is composed mostly of nonliving extracellular matrix, consisting of ground substance & fibers which separates, often widely, the living cells of the tissue. (Other primary tissues are mostly composed of cells)

5 Types of Connective Tissue Proper 1 – Loose Connective Tissue – 1) Areolar connective tissue - gel-like matrix with all three connective tissue fibers (collagen, elastic, & reticular) serves to bind body parts together while allowing them to move freely over one another wraps small blood vessels & nerves, surrounds glands, & cushions organs is widely distributed throughout body

6 Connective Tissue Proper: Loose Figure 4.9a

7 Connective Tissue Proper: Loose 2) Adipose connective tissue – (fat) richly vasculatized tissue that is similar to areolar connective tissue with closely packed adipocytes – Functions: 1- reserves food stores 2- insulates against heat loss 3- supports 4 - protects

8 Connective Tissue Proper: Loose – Found under skin, around kidneys, within abdomen, & in breasts – Local fat deposits serve nutrient needs of highly active organs

9 Connective Tissue Proper: Loose Figure 4.9b

10 Connective Tissue Proper: Loose 3) Reticular connective tissue – loose ground substance with reticular fibers – Reticular cells lie in a fiber network – Forms a soft internal skeleton, or stroma, that supports other cell types – Found in lymph nodes, bone marrow, & spleen

11 Connective Tissue Proper: Loose Figure 4.9c

12 Types of Dense Connective Tissue 2 - Dense Connective Tissue - all have fibers – Also called fibrous connective tissues – 1) Dense Regular connective tissue - contain closely packed bundles of parallel collagen fibers (running in same direction) with a few elastic fibers – Makes up tendons & ligaments

13 Connective Tissue Proper: Dense Regular Figure 4.9d

14 Types of Dense Connective Tissue 2) Dense Irregular Connective Tissue – contains thick bundles of collagen fibers arranged in an irregular way with some elastic fibers – can withstand tension in many directions providing structural strength – is found in dermis & submucosa of digestive tract

15 Connective Tissue Proper: Dense Irregular Figure 4.9e

16 Types of Cartilage 1- Hyaline Cartilage – (gristle) most abundant cartilage in body Matrix has network of collagen fibers Functions: 1) supports 2) reinforces 3) cushions & 4) resists compression **provides firm support with some pliability Found in embryonic skeleton, end of long bones, nose, trachea, & larynx

17 Types of Dense Connective Tissue 2 - Dense Connective Tissue - all have fibers – Also called fibrous connective tissues – 1) Dense Regular connective tissue - contain closely packed bundles of parallel collagen fibers (running in same direction) with a few elastic fibers – Makes up tendons & ligaments

18 Connective Tissue Proper: Dense Regular Figure 4.9d

19 Types of Dense Connective Tissue 2) Dense Irregular Connective Tissue – contains thick bundles of collagen fibers arranged in an irregular way with some elastic fibers – can withstand tension in many directions providing structural strength – is found in dermis & submucosa of digestive tract

20 Connective Tissue Proper: Dense Irregular Figure 4.9e

21 Types of Cartilage 1- Hyaline Cartilage – (gristle) most abundant cartilage in body Matrix has network of collagen fibers Functions: 1) supports 2) reinforces 3) cushions & 4) resists compression **provides firm support with some pliability Found in embryonic skeleton, end of long bones, nose, trachea, & larynx

22 Connective Tissue: Hyaline Cartilage Figure 4.9f

23 Types of Cartilage 2- Elastic Cartilage – nearly identical to hyaline cartilage but with more elastic fibers Maintains shape & structure while allowing flexibility Supports external ear (pinna) & epiglottis

24 Connective Tissue: Elastic Cartilage Figure 4.9g

25 Types of Cartilage 2- Fibrocartilage – structuaral intermediate between hyaline cartilage & regular connective tissues & has matrix similar to hyaline cartilage but less firm with thick collagen fibers found where strong support & the ability to withstand heavy pressure are required such as the intervertebral discs & in discs of knee joint provides tensile strength & absorbs compression shock

26 Connective Tissue: Fibrocartilage Cartilage Figure 4.9h

27 Connective Tissue: Bone (Osseous Tissue) Bone - hard, calcified matrix with collagen fibers – also called osseous tissue Osteocytes (mature bone cells)are found in small spaces called lacunae & are well vascularized with blood vessels has exceptional ability to support & protect body structures due to its hardness, which is determined by collagen fibers & calcium salts found in extracellular matrix

28 Connective Tissue: Bone (Osseous Tissue) Figure 4.9i

29 Connective Tissue: Blood Blood – consists of red & white blood cells & plasma proteins in a fluid matrix (plasma) – contained within blood vessels – functions in the transport of respiratory gases, nutrients, & wastes – is classified as a connective tissue because it developed from mesenchyme

30 Connective Tissue: Blood Figure 4.9j

31 Nervous Tissue Nervous Tissue – main componenet of nervous system Neurons – highly specialized branched nerve cells with long cellular processes that generate & conduct nerve impulses – dendrites – respond to stimuli – axons – carry impulses away from nerve cell body – support cells – transmits electrical signals from sensory receptors to effectors Found in the brain, spinal cord, and peripheral nerves

32 Nervous Tissue Support cells – nonconducting cells that support, insulate, & protect delicate neurons Neurons are found in brain, spinal cord, & peripheral nerves

33 Nervous Tissue Figure 4.10

34 Types of Muscle Tissue Muscle Tissue – highly cellular, well-vascularized – responsible for most types of body movement 1- Skeletal Muscle - attaches to bones of skeleton – Forms flesh of body & cause voluntary movement – Skeletal muscle cells (called muscle fibers) are long, cylindrical, multinucleate cells with striations

35 Muscle Tissue: Skeletal Figure 4.11a

36 Types of Muscle Tissue 2- Cardiac Muscle - branching, striated, uninucleate cells interlocking at intercalated discs – responsible for involuntary movement of heart 3- Smooth Muscle – has no striations – propels substances along internal passageways (i.e., peristalsis) – found in walls of hollow organs – is involuntary muscle

37 Nervous Tissue Support cells – nonconducting cells that support, insulate, & protect delicate neurons Neurons are found in brain, spinal cord, & peripheral nerves

38 Nervous Tissue Figure 4.10

39 Types of Muscle Tissue Muscle Tissue – highly cellular, well-vascularized – responsible for most types of body movement 1- Skeletal Muscle - attaches to bones of skeleton – Forms flesh of body & cause voluntary movement – Skeletal muscle cells (called muscle fibers) are long, cylindrical, multinucleate cells with striations

40 Muscle Tissue: Skeletal Figure 4.11a

41 Types of Muscle Tissue 2- Cardiac Muscle - branching, striated, uninucleate cells interlocking at intercalated discs – responsible for involuntary movement of heart 3- Smooth Muscle – has no striations – propels substances along internal passageways (i.e., peristalsis) – found in walls of hollow organs – is involuntary muscle

42 Muscle Tissue: Cardiac Figure 4.11b

43 Muscle Tissue: Smooth Figure 4.11c

44 Coverings & Lining Membranes Some of the body’s membranes incorporate more than 1 type of tissue. 1 – Cutaneous Membrane - cutis = skin – Consists of stratified squamous epithelium firmly attached to a thick layer of dense irregular connective tissue (dermis)

45 Coverings & Lining Membranes 2- Mucous Membrane– also called mucosae – line body cavities such as those of hollow organs of digestive, respiratory, & urogenital tracts that open to exterior & contain either stratified squamous or simple columnar epithelia

46 Coverings & Lining Membranes 3 – Serous Membrane – moist membranes found in closed ventral body cavities – consists of stratified squamous epithelium resting on a thin layer of loose connective (areolar) tissue – Are named by where they are located Pleura = lungs Pericardium = covering of heart Peritoneums = coverings in abdominopelvic cavity

47 Tissue Repair Steps of Tissue Repair – 1- Inflammation – caused by tissue trauma & is characterized by dilation of blood vessels, increase in vessel permeability, redness, heat, swelling, & pain – Blood clot forms

48 Tissue Repair 2 – Organization restored the blood supply. – Blood clot is replaced with granulation tissue 3 – Regeneration & Fibrosis If wound is small & damaged tissue can divide, the tissue will regenerate & cover the fibrous tissue When wound is extensive or damaged tissue cannot divide, it is repaired only by fibrous connective (scar) tissue.

49 Developmental Aspects 3 primary germ layers for early during embryonic development & becomes specialized into the 4 types of tissues. – Ectoderm – top layer - nervous tissue comes from ectoderm – Mesoderm – middle layer – muscle & connective tissue come from mesoderm – Endoderm – inside layer – organs Epithelium arises from all 3 primary germ layers


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