CELL BIOLOGY Peng Xi Peking University. Outline Cell ― Structure ― Cell process Tissue ―...
-
Upload
audra-walters -
Category
Documents
-
view
217 -
download
1
Transcript of CELL BIOLOGY Peng Xi Peking University. Outline Cell ― Structure ― Cell process Tissue ―...
CELL BIOLOGY
Peng Xi
Peking University
Outline
Cell― Structure
― Cell process
Tissue― Morphology
― Function
Cell
Target that Biomedical optics study:― Cell( Including subcellular organelles)
― Tissue (Including organs and body)
Cell― In vivo 活体― Ex vivo 死体
Tissue― In situ 原位― In vivo 活体― Fixed
http://www.tokresource.org/tok_classes/biobiobio/biomenu/cell_theory/index.htm
Structure of cell
Plasma membrane
Cell wall― Prokaryotic cell
― Eukaryotic plant cell
Cytoplasm
Cytosol 胞液 Organelle
Nucleus
原核细胞
真核细胞
Plasma membrane 质膜
A semipermeable outer boundary of both prokaryotic and
eukaryotic cells. This outer membrane, about 4–5nm
thick, is a continuous sheet of a double layer (bilayer) of
long-chain molecules called phospholipids.
A phospholipid molecule has a long tail of alkyl 烷基chain, which is hydrophobic (repels water), and a
hydrophilic head (likes water) which carries a charge (and
is thus ionic).
Phospholipid molecules
spontaneously orient (or
self-organize) to form a
bilayer in which the
hydrophobic tails are
pointed inwards (shying
away from the outer
aqueous environment).
The hydrophilic, ionic
head groups are in the
exterior and are thus in
contact with the
surrounding aqueous
environment.
Cytoplasm 细胞质
Cytoplasm represents everything enclosed by the plasma
membrane, with the exclusion of the nucleus.
It is present in all cells where metabolic reactions occur.
Consists mainly of a viscous 粘性 fluid medium that
includes salts, sugars, lipids, vitamins, nucleotides, amino
acids, RNA, and proteins which contain the protein
filaments, actin microfilaments, microtubules, and
intermediate filaments.
Many of the functions for cell growth, metabolism, and
replication are carried out within the cytoplasm.
Cell skeleton 细胞骨架
Network of fibers composed of proteins
Three kinds:― Microtubule (25nm)
― Intermediate filaments (10nm)
― Actin filaments (8nm)
Cell skeleton 细胞骨架
Main functions:― Establish the cell shape
― Provide mechanical strength to the cell
― Perform muscle contraction
― Control changes in cell shape and thus produce locomotion
― Provide chromosome separation in mitosis (有丝分裂) and
meiosis (减数分裂)― Facilitate intracellular transport of organelles
Nucleus 细胞核
The nucleus is often called the control center
of the cell. It is the largest organelle in the cell,
usually spherical with a diameter of 4–10 μm,
and is separated from the cytoplasm by an
envelope consisting of an inner and an outer
membrane. All eukaryotic cells have a nucleus.
The nucleus contains DNA distributed among
structures called chromosomes 染色体 , which
determine the genetic makeup of the
organism. The chromosomal DNA is packaged
into chromatin fibers by association with an
equal mass of histone proteins 组蛋白 .
The nucleus contains openings (100nm across)
in its envelope called nuclear pores, which
allow the nuclear contents to communicate
with the cytosol. Ribosome 核糖体
Nucleus 细胞核
The inside of the nucleus also contains another
organelle called a nucleolus 核仁 , which is a
crescent-shaped 月牙形 structure that
produces ribosomes by forming RNA and
packaging it with ribosomal protein. The
nucleus is the site of replication of DNA and
transcription into RNA. In a eukaryotic cell,
the nucleus and the ribosomes work together
to synthesize proteins.
Ribosome 核糖体
Mitochondria 线粒体
Cell “power plant”
Shape: fat sausage, 0.5-1.5um wide and 3-10um long.
20% of the cytoplasmic volume
NADH + H+ + 3 ADP + 3 Pi + 1/2 O2 NAD+ + 4 H2O + 3 ATP
FADH2 + 3 ADP + 3 Pi + 1/2 O2 FAD + 4 H2O + 3 ATP
Endoplasmic reticulum(ER) 内质网
ER consists of flattened sheets,
sacs, and tubes of membranes
that extend throughout the
cytoplasm of eukaryotic cells and
enclose a large intracellular
space called lumen. There is a
continuum of the lumen between
membranes of the nuclear
envelope. The rough endoplastic
reticulum (rough ER) is close to
the nucleus, and is the site of
attachment of the ribosomes.
Endoplasmic reticulum(ER) 内质网
Ribosomes 核糖体 are small and dense structures, 20nm in diameter,
that are present in great numbers in the cell, mostly attached to the
surface of rough ER, but can float free in the cytoplasm. They are
manufactured in the nucleolus of the nucleus on a DNA template and
are then transported to the cytoplasm. They consist of two subunits of
RNA (a large, 50S, and a small, 30S) that are complexed with a set of
proteins.
Ribosomes are the sites of protein synthesis. The process of protein
synthesis uses a messenger RNA template.
The rough ER transitions into a smooth endoplastic reticulum
(smooth ER), which is generally more tubular and lacks attached
ribosomes.
The smooth ER is the primary site of synthesis of lipids and sugars
and contains degradative enzymes, which detoxify many organic
molecules.
Others
Glogi apparatus 高尔基体― Shipping and receiving dept. for protein
Lysosome 溶酶体― Bags of hydrolytic enzymes that are 0.2-0.5um
Peroxisome 过氧物酶体― Membrane bound vesicles containing oxidative enzymes
Chloroplast 叶绿体 (only in plant cell)― Site of photosynthesis
Types of cells
Epithelial cell 上皮细胞― Form sheets called epithelia to line the inner and outer surface of the
body. Most are squamous cells 鳞状细胞 .
Blood cell
Nerve cell (neuron)
Sensory cell
Germ cell 生殖细胞 Stem cell
Erythrocytes (Red blood cell)― 7-9um diameter, no nuclei
― Contain hemoglobin which can
bind O2
― 1cm cube blood: 5 billion RBC
Leucocyte (White blood cell)― WBC:RBC=1:1000
― Lymphocyte 淋巴细胞 • T cell: cell mediate immunity
• B cell: produce antibody
― Macrophages 巨噬细胞 and
neutrophils 中性白细胞
Thrombocyte (Platelet)― Produce specific substances for
blood coagulation
http://kids.britannica.com/elementary/art-88528/Blood-is-made-up-of-red-blood-cells-white-blood
Question: What kind of blood cell has to be diagnosed for
HIV infection?
http://www.thebody.com/content/art2494.html
HIV and T-cell (CD4)
Early in the course of the disease, the body can make more
CD4 cells to replace the ones that have been damaged by
HIV. Eventually, the body can't keep up and the number of
functioning T-cells decreases. As more and more CD4 cells
become damaged, the immune system becomes more and
more weakened. Eventually, the weakened immune system
leaves the body at risk for illness and infection.
http://aids.about.com/od/technicalquestions/f/cd4.htm
STEM CELLS….______ Inner cell mass becomes the baby
全能
桑椹胚
多能性
囊胚
内细胞团
Stem cell
The Nobel Prize in Physiology or Medicine 2012
The Nobel Prize in Physiology or Medicine 2012 was
awarded jointly to Sir John B. Gurdon and Shinya
Yamanaka "for the discovery that mature cells can be
reprogrammed to become pluripotent"
Cellular processes
Replication
Biosynthesis
Energy production
Signaling
Death
Transformation
Replication
Question: How a biological being can survive for
evolution?
Driving force in life: replicate for the continuing survival
of the species.
Cell Death
Death is a necessary part of life.
Apoptosis 细胞凋亡― Programmed Cell Death (suicide)
1. Cells infected with a virus
2. Cells of the immune systems
3. Cells with DNA damage
Cell killing― Cell death by injury, accidental cell death
― Mechanical damage or toxic chemicals
Cell that won’t regularly suicide: cancer cells
http://www.fitnesssutra.com/2010/09/13/sun-bath-and-its-importance-to-health/
Cell transformation
Permanent inheritable alteration of cell
Uptake and incorporation of foreign DNA― Virus
― Cancer causing agents such as mutagens 基因突变― Oncogenesis 肿瘤 properties
Cancer proliferation and screening
Cancer is different with normal cells in:• Cell metabolism;• Cell morphology.
Squamose cell cancer
Normal skinCarcinoma cells
http://tissupath.com.au/medical-student-subjects-skin/
http://networks.lww.com/pathology/blog/iow/pages/default.aspx
Histology: ex vivo, invasive
•Cannot evaluate the progress/cure effectiveness
•Trigger the cancer growth from benign to malign
Tissues
This part of ppt is originated from www.lavc.edu/instructor/watson_k/docs/Tissues.ppt
Tissues
Definition: a group of closely associated cells that perform related functions and are similar in structure
Between cells: nonliving extracellular material
Four basic types of tissue…functionEpithelium…coveringConnective tissue…supportMuscle tissue…movementNervous tissue…control
Epithelia 上皮 (plural) Epithelium: sheet of cells that covers a body
surface or lines a body cavity; also form most of the body’s glands
Roles: as interfaces and as boundaries Functions:
Protection Absorption
Sensory reception Ion transport
Secretion Filtration
Formation of slippery surfaces for movement
Special characteristics of epithelia
Cellularity 多孔性 Specialized contacts 触体 Polarity
Free upper (apical) surface Lower (basal) surface contributing basal lamina to
basement membrane Support by connective tissue Avascular 无血管 but innervated 有神经
Without vessels With nerve endings
Regeneration 再生
Classification of epithelia
According to thickness“simple” - one cell layer“stratified” – more than one layer of cells
(which are named according to the shape of the cells in the apical layer)
According to shape“squamous” – wider than tall“cuboidal” – as tall as wide“columnar” - taller than wide
to protect
where diffusion is important
where tissues are involved in secretion and absorption: larger cells because of the machinery of production, packaging, and energy requirements
“ciliated” literally = eyelashes(see next page)
气管
Stratified: regenerate from below
Rare…
Rare…
Endothelium 内皮 A simple squamous
epithelium that lines the interior of the circulatory vessels and heart
Mesothelium 间皮
Simple squamous epithelium that lines the Peritoneal 腹膜 , pleural 胸膜 and pericardial 心包 cavities and covers the viscera 内脏
Glands 腺体 Epithelial cells form them Production & secretion of needed
substances Are aqueous (water-based) products The protein product is made in rough ER,
packed into secretory granules by Golgi apparatus, released from the cell by exocytosis 胞外分泌
Classification of glands
By where they release their productExocrine 外分泌 : external secretion onto body
surfaces (skin) or into body cavitiesEndocrine 内分泌 : secrete messenger
molecules (hormones) which are carried by blood to target organs; “ductless” glands By whether they are unicellular or multicellular
Exocrine glands 外分泌腺unicellular or multicellular
Unicellular: goblet cell 杯状细胞 scattered within epithelial lining of intestines and respiratory tubes 呼吸道
Product: mucin 粘蛋白mucus 黏液 is mucin & water
Multicellular exocrine glands
Epithelium-walled
duct and a
secretory unit
Examples of exocrine gland products
Many types of mucus 黏液 secreting glands
Sweat glands of skin Oil glands of skin Salivary glands of mouth 唾液 Liver (bile) 胆汁 Pancreas (digestive enzymes) 胰脏 Mammary glands (milk) 乳腺
Endocrine glands
Ductless glands
Release hormones into extracellular spaceHormones are messenger molecules
Hormones enter blood and travel to specific target organs
Epithelial surface features
Lateral surface 水平面Adhesion proteinsTongue and groove wavy contoursCell junctions: see next slide
Basal surface 基底面Basal lamina: noncellular sheet of protein
together with reticular fibers form basement membrane
Apical surface 顶面
Cell Junctions Tight junctions
So close that are sometimes impermeable
Adherent junctions 粘附连接 Transmembrane linker
proteins Desmosomes 桥粒
Anchoring junctions Filaments anchor to the
opposite side Gap junctions
Allow small molecules to move between cells
Apical surface features
Microvilli 微绒毛 – maximize surface areaFingerlike extensions of the plasma
membrane of apical epithelial cellsOn moist and mucus secreting epitheliumLongest on epithelia that absorb nutrients
(small intestine) or transport ions (kidneys)
Four basic types of tissue
EpitheliumConnective tissue
Connective tissue proper (examples: fat tissue, fibrous tissue of ligaments)
Cartilage Bone Blood
Muscle tissueNervous tissue
Classes of Connective Tissue: note the cell types and great variety of subclasses
成纤维细胞 成软骨细胞 造骨细胞 成血干细胞
间叶细胞
Connective Tissue Originate from embryonic tissue called
mesenchyme 间叶细胞 Most diverse and abundant type of tissue Many subclasses (see previous slide) Function: to protect, support and bind together
other tissues Bones, ligaments, tendons Areolar cushions; adipose insulates and is food
source Blood cells replenished; body tissues repaired
Cells separated from one another by large amount of nonliving extracellular matrix
Extracellular Matrix explained
Nonliving material between cells Produced by the cells and then extruded Responsible for the strength Two components
1. Ground substance Of fluid, adhesion proteins, proteoglycans 蛋白多
糖 Liquid, semisolid, gel-like or very hard
2. Fibers: collagen, elastic or reticular
Basic functions of connective tissue reviewed
Support and binding of other tissues Holding body fluids Defending the body against infection
macrophages, plasma cells, mast cells, WBCs Storing nutrients as fat
Classes of Connective Tissue
*
间叶细胞
Mesenchyme 间质
aerolar tissue粘贴组织
lamina propria 黏膜肌层
collagen, elastin and reticular fibers
Adipose 脂肪
Reticular 网状层
*
Classes of Connective Tissue
aponeurosis 腱膜
*
Classes of Connective Tissue
腔隙
肋软骨
透明
软骨细胞
Classes of Connective Tissue
*
Classes of Connective Tissue
*
Membranes that combine epithelial sheets plus underlying connective tissue proper (see next slide)
Cutaneous membranes Skin: epidermis and dermis
Mucous membranes, or mucosa Lines every hollow internal organ that opens to the
outside of the body Serous membranes, or serosa
Slippery membranes lining the pleural, pericardial and peritoneal cavities
The fluid formed on the surfaces is called a transudate Synovial membranes
Line joints
(a) Cutaneous membrane
(b) Mucous membrane
(c) Serous membrane
Four basic types of tissue
EpitheliumConnective tissueMuscle tissue
Skeletal Cardiac Smooth
Nervous tissue
Four basic types of tissue
EpitheliumConnective tissueMuscle tissueNervous tissue
NeuronsSupporting cells
Summary
All living creatures are made up of cells.
Biological systems are classified as viruses (non-self-
replicating), prokaryotes (no well-defined nucleus), and
eukaryotes (well-organized cell and nucleus).
Living systems are aggregates of water, amino acids,
carbohydrates, fatty acids, ions, and other
macromolecules called biopolymers (e.g., DNA, RNA, and
proteins).
Cells undergo differentiation to form different types of
cells and as-semble to form tissues, which organize to
form organs with different functions. Various organs
integrate to form an organism.
Summary
A plasma membrane consists of a structure lipid bilayer that forms a
semipermeable boundary around the cell. The membrane controls the
transport of food, water, ions, and signals.
The interior contents of a cell, enclosed by the membrane, consists of
various organelles (compartments) such as the cytoplasm,
cytoskeleton, nucleus, mitochondria, endosplasmic reticulum (ER),
Golgi apparatus, lysosomes, and peroxisomes. Plant cells have an
additional organelle, called the chloroplast .
Cytoplasm consists of the entire contents of a cell (except the nucleus)
enclosed by a membrane. Cytoplasm forms the center of activities
such as cell growth, metabolism, and replication
Summary
Important cellular processes are: (i) cell replication to
produce DNA and, subsequently, new cells; (ii) cell
biosynthesis by a process of transcription to produce RNA
and a process of translation to synthesize protein; (iii) cell
energy production in a usable form; (iv) cell signaling to
initiate processes in adjacent and distant cells; (v) cell
death by programmed cell death and death due to injury;
and (vi) cell transformation that produces a tumor.
The constituents of a tissue are: (i) various cells; (ii) cell-adhesion
molecules which bind cells to one another; (iii) extracellular matrix
filling the space between cells; and (iv) the cell junctions.
The extracellular matrix helps to bind the cell, acts as a reservoir for
hormones controlling cell growth and differentiation, and provides a
lattice through which cells can move.
Cell junctions stabilize cell–cell infrastructure and facilitate
communication between neighboring cells.
Tumors consist of cells with structural changes produced by
transformation that show aberration in the normal behavior.
Cancer is a special type of tumor that exhibits much more rapid
multiplication (proliferation) of cells compared to normal cells.
Thank you!