Learning objectives
Describe the major functional differences among the four tissue types
Describe the structure and function of the 5 types of epithelia
How is the organization of epithelial tissue anatomically defined?
Describe the structural and functional differences between endocrine and exocrine glands
Describe the three different ways cells can be connected to each other
Describe the structure and function of the different classes and subclasses of connective tissue
Describe the differences between the three types of cartilage
Describe the structure and function of nervous tissue, and the structure of a ’typical’ neuron
Know the functional differences between the different parts of the neuron
Describe the structure and function of the three different types of muscles, being able to distinguish the unique characteristics of each
PPT
Nerve tissue
*nissl bodies : Nissl bodies (also called Nissl granules, Nissl substance or tigroid substance) are discrete granular structures in neurons that consist of rough endoplasmic reticulum, a collection of parallel, membrane-bound cisternae studded with ribosomes on the cystosolic surface of the membranes.
*neurilemma : Neurilemma (also known as neurolemma, sheath of Schwann, or Schwann's sheath) is the outermost nucleated cytoplasmic layer of Schwann cells (also called neurilemmocytes) that surrounds the axon of the neuron.
*axon hilock : The axon hillock is a specialized part of the cell body (or soma) of a neuron that connects to the axon. It can be identified using light microscopy from its appearance and location in a neuron and from its sparse distribution of Nissl substance. Axon hillock. Red labeled is pointing directly at the axon hillock.
*cerebrospinal fluid 뇌척수액
< Glial cells in the CNS > 종류, 역할 다 알아야 함 !
*Astrocyte - abundant, help space and maintain neurons in CNS
*Microglial cell - become macrophage-like when needed
*Ependymal cell - line the ventricles where CSF is secreted, cila help circulate CSF
*Oligodendrocyte - equivalent of Schwann cells in CNS
*Sensory neuron with Schwann cell and satellite cells
Muscle tissue
*Can muscle cells divide/ increase in number following exercise?
Although muscle cells can change in size, new cells are not formed when muscles grow. Instead, structural proteins are added to muscle fibers in a process called hypertrophy, so cell diameter increases.
*In what situation is a problem with that Cardiac muscle with little or no capacity for cell division?
The centrosome is an organelle found in almost every cell. In recent years, experiments have shown that
if the centrosome is not intact, the cell can no longer reproduce.
*excitable
*skeletal muscle is always voluntary?
*functional syncytium
A functional syncytium is a unit of contraction comprised of a network of electrically connected cardiac muscle cells. Functional syncytium allows the heart to work as a unit. The wave of contraction begins with pacemaker cells, and they are self-excitable. They depolarize to threshold and fire action potential
the individual cells work with adjacent cells for coordinated action.
A large cell-like structure formed by the joining together of two or more cells.
| Skeletal muscle | Smooth muscle | Cardiac muscle (myocardium) |
| -striated, voluntary -movement, posture -If there are no motor nerve signals, there is no contraction |
-involuntary, high capacity for stretch -follows in tubes and hollow organs -control rates of flow, bulk movement, secretion/excretions to be expelled, -autorythmic |
-involuntary -little or no capacity for cell division |
Epithelia
*avascular refers to not containing blood vessels or lymphatic system
*The extracellular matrix helps cells to bind together and regulates a number of cellular functions, such as adhesion, migration, proliferation, and differentiation.
*Basement membrane ( basal lamina, reticular lamina ) is avascular and always connects epithelial tissue to loose connective tissue below it
*BM supports epithelial tissue, protects epithelial tissue from becoming damaged, prevents maligant cells entering deeper tissue.
(maligant :very virulent or infectious.)
*The endothelium is a thin membrane that lines the inside of the heart and blood vessels. Endothelial cells release substances that control vascular relaxation and contraction as well as enzymes that control blood clotting, immune function and platelet (a colorless substance in the blood) adhesion.
Endothelium is the thin lining of inside the blood vessels.
*goblet cells : have cilia and the layer may contain muscus secreting unicellular glands
*Simple squamous epithelium locate in endothelium (surface of all blood vessels), wall of alveolar sacs in lung, and mesothelium (body cavities). The primary function of simple squamous epithelia is to facilitate diffusion of gases and small molecules.
*Mucociliary escalator (mucus and cilia)
The mucociliary escalator is inside of the conducting airways and is made up of mucus and cilia, which moves the mucus up and out of the lungs where it can be expelled by coughing or swallowing
consist of mucus and cilia. CIlia moves mucus up and out to expell something from the surface.
(digestive tract, galbladder, excretody ducts, small bronchi, uterine tubes, other regions of the uterus
exocrine glands secrete substances to the epithelial surface and endocrine glands secrete substances such as hormones into the blood vessels.
Exocytosis is when the cell send materials from inside to outside, extracellular space.
*Main structural difference between an exocrine and endocrine gland?
The key difference between the two types is
exocrine glands secrete substances into a ductal system to an epithelial surface, endocrine glands secrete products directly into the bloodstream
Exocrine secretes substances outside surface of the body with ducts and endocrine glands secrete substances to the blood stream
Endocytosis involves cells taking in substances from outside the cell by engulfing them in a vesicle derived from the cell membrane. Exocytosis is where cells shift materials, such as waste products, from inside the cell to the extracellular space.
Tublar gland has a tublar shape of gland and the lumen is also tubular shaped.
Acinar gland has a spherical shape of gland with a small lumen
Areolar gland has a spherical shape with a larger lumen.
*Merocrine gland vs holocrine gland
merocrine gland : secrete their products by exocytosis/ release only an acellular secretory product
(sweat, pancreatic enzymes, saliva)
holocrine gland : the entire secretory cell ruptures, releasing secretions and dead cell fragments
(sebaceous gland of the skin)
(기름 샘과 눈꺼풀판 샘의 경우처럼 세포질에서 분비물을 합성하여 저장하였다가 세포질과 분비물 전체가 분비물로서 방출된다.)
Merocrine and holocrine glands are exocrine glands, and both glands have the function of secretion. Merocrine glands have the ability to secrete substances without causing any damage to the cells. In contrast, holocrine glands destroy the cells when secreting substances.
Meocrine and Holocrine are all exocrine glands. Meocrine secretes substances by exocytosis, however Holocrine secretes its substances by rupturing cells themselves and leaving dead cell fragments.
-Tight junction : are linked by tight juctions, impermeable to large molecules, but many allow movement of small molecules, often selectively.
-Desmosomes : spot-welds, which physically hold cells together physically: common where wear, tear occurs
(skin, large mechanic stress occurs/ eg. heart)
-Gap junction : refer to a "gap" linking (not seperating) the cells,
(adjacent cells are in physical continuum, this allows for transfer of cytoplasm and other things, including electrical signals, allowing linked cells to act together seen in groups of cardiac muscle cells, for example)
*Why Carcinoma accounts for the highest factor of all cancers?
Epithelial tissue is the covering/lining of the body, It is the first tissue to counter cancer.
We can also group cancer according to the type of cell they start in. There are 5 main groups. These are:
- carcinoma – this cancer begins in the skin or in tissues that line or cover internal organs. There are different subtypes, including adenocarcinoma, basal cell carcinoma, squamous cell carcinoma and transitional cell carcinoma
- sarcoma – this cancer begins in the connective or supportive tissues such as bone, cartilage, fat, muscle or blood vessels
- leukaemia – this is cancer of the white blood cells. It starts in the tissues that make blood cells such as the bone marrow.
- lymphoma and myeloma – these cancers begin in the cells of the immune system
- brain and spinal cord cancers – these are known as central nervous system cancers
connective tissue
*Fibroblast : fibrocyte -> connective tissue
connective tissue > 1. loose connective tissue (Areolar, Adipose, Reticular)
2. dense connective tissue (Regular, Irregular, Elastic)
*Chondroblast : Chondrocyte -> Cartilage
cartilage > 1. hyaline cartilage : end of long bone, epiphyseal plate,connection between ribs and sternum
2. fibrocartilage : intervertebral discs, pubic symphisis, discs of knee joint
3. elastic cartilage : ears
*Osteoblast : Osteocyte -> Osseous (bone)
bone > 1. compact bone
2. spongy bone (cancellous bone)
*Hemaopoietic stem cell : Blood cells(macrophage) -> Blood
fiber -> elastic, collagen, reticular
cartilage -> hyaline, elastic, fibrous
loose connective tissue -> areolar, adipose, reticular
dense connective tissue -> regular, irregular, elastic
*areolar, adipose, reticular
*regular, irregular, elastic
*elastic,collagen,reticular -> fiber
*hyaline, elasic, fibrous -> cartilage
*cartilagenous, fibrous, synovial -> joint
Oedema is a build-up of fluid in the body which causes the affected tissue to become swollen. The swelling can occur in one particular part of the body or may be more general, depending on the cause.
Odema is the state that tissue become swollen. Mostly areolar tissue absorb fluids and stretches.
*Macrophage
: type of white blood cell that helps eliminate foreign substances by engulfing foreign materials and initiating an immune response.
*Lymphocyte
: A type of immune cell that is made in the bone marrow and is found in the blood and in lymph tissue. The two main types of lymphocytes are B lymphocytes and T lymphocytes. B lymphocytes make antibodies, and T lymphocytes help kill tumor cells and help control immune responses.
*Mast cells
: play an important role in how the immune system responds to certain bacteria and parasites and they help control other types of immune responses.They contain chemicals such as histamine, heparin, cytokines, and growth factors.
*Neutrophil
: A type of white blood cell that is an important part of the immune system and helps the body fight infection. When microorganisms, such as bacteria or viruses, enter the body, neutrophils are one of the first immune cells to respond.
-> They are all belong to immune system
*Adipose tissue is the only example where the extracellular matrix does not primarily determine function of tissue. How come?
The main differences between adipose tissue and other connective tissues are that adipose tissue is made of a different type of cell, there are much fewer fibers, and there is no true matrix in the tissue.
*Triacylglycerols are the form in which fat energy is stored in adipose tissue. Triacylglycerols are sometimes referred to as triglycerides. (1 glycerol, 3 fatty acid)
Triglyceride is the form of storing fat in adipose tissue.
* amorphous : without a clearly defined shape or form.
* resilient : 탄력있는
*What are the consequences for healing damaged tissue?
Injured tissues release chemicals. In response, the body increases circulation to the injured area, bringing white blood cells and nutrients. The injured area and tissues surrounding it become swollen, warm and reddened. The inflammatory response limits function (because it causes more pain) to help the tissues heal.
As debris from damaged tissues is removed, the inflammatory phase gradually subsides and the tissue begins to repair and rebuild itself. New blood vessels grow into the area to deliver repair “supplies” and remove waste. Scar tissue begins to form. Although symptoms improve, the injured area should still be protected and not overused, as damage will occur.
In remodeling, a dense network of strong collagen fibers begins to replace the initial scar tissue. The fiber network adapts to the demands placed on it to ensure that the damaged area will move freely and be strong enough to function correctly. In some cases, adhesions form between muscle layers and painful trigger points may develop. Full remodeling may take months or even years.
a. Hyaline cartilage is the most abundant cartilage, providing firm support with some pliability.
(It lines your joints and caps the ends of your bones. Hyaline cartilage at the ends of your bones is sometimes referred to as articular cartilage.)
covers the ends of long bones in joint cavities; forms costal cartilages of the ribs; cartilages of the nose, trachaea, and larnyx
b. Elastic cartilage is found where strength and exceptional stretch are needed, such as the external ear and epiglottis
c. Fibrocartilage is found where strong support and the ability to withstand heavy pressure are required, such as the intervertebral discs.
epiglottis 후두개
We know that they contain nerves that it hurts when we get fracture on the bone.
Broken bone can be remodelled and it means they are vcascular as the blood can bring nutrients to the damagend area to be healed.
Fibrocartilage is found in intevertebral discs and pubic symphysis
Hyaline cartilage is found in the end of long bone, costal cartilage of ribs (connection between sternum and ribs)
Elastic cartilage is found in ears and (epiglottis)
stratified squamous epithelial tissue -> skin
Self paced quiz
Summary
*Smooth muscle location, function, shape and characteristic
*Cardiac muscle
*Skeletal muscle
*Glial cells types and each functions
*Cell nuclei reflect cell shape, flattened in flattened squamous cells, elongated in a columnar cell
*Transitional and pseudo stratified epithelial tissue?
*Cells that line tissues and define body compartments (tall box- like dilated cells in the respiratory tract (the mucociliary escalator- what does this achieve?)
*Know what fibrocytes do
*What do these term mean, and which organ/system in particular is characterised by an extensive, intrinsic nerve supply?
*What are the main glial cells encountered in the CNS?
BLOOD VESSEL
blood vessels are comprised of three different tissue types.
Blood contained in the blood vessels is connective tissue.
Smooth muscles help blood vessel to transport blood by expanding and contracting the blood vessels.
They regulate the rate of the flow.
Lastly, simple squamous epithelial tissue is the lining of the blood vessel. epithelial tissue inside the blood vessels are called endothelium. They easily transport CO2 and O2 between blood.
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