Chapter 3: The cells, tissues and organisation of the body Flashcards
(85 cards)
1
Q
Cells
A
Are the smallest functional unit of the body
2
Q
Cells are grouped together to form
A
Tissues
3
Q
Different tissues are grouped together to form
A
Organs
4
Q
Organs are grouped together to form
A
Systems
5
Q
Zygote
A
The human body develops from a single cell, which is the result of the fusion of the ovum and the spermatozoon
6
Q
A cell consists of
A
Plasma membrane
Cytoplasm
Organelles - incl Nucleus
7
Q
Types of organelles
A
Nucleus, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes and cytoskeleton
8
Q
Plasma membrane
A
Two layers of phospholipids with protein and sugar molecules embedded in them, plus lipid cholesterol is present.
9
Q
Phospholipid
A
Hydrophillic, electrically charged head
Hydrophobic, no charge tail
10
Q
Nucleus
A
Is the largest organelle and contained within the nuclear envelope with pores in order for substances to pass between it and the cytoplasm
11
Q
Nucleus contains the genetic material
A
46 chromosomes - DNA
12
Q
Chromatin
A
During cell division the chromosomes resemble a fine network of threads
13
Q
A roughly spherical structure contained within the nucleus
A
Nucleolus
14
Q
Mitochondria
A
Sausage shaped structure
Power house of the cell
Synthesis of ATP
15
Q
Ribosomes
A
- Tiny granules composed of RNA and protein
- Synthesise proteins from amino acids
- Found on the outer surface of the nuclear envelop or on rough endoplasmic reticulum
16
Q
Endoplasmic reticulum
A
- Extensive series of interconnecting membranous canals in the cytoplasm
- Smooth ER synthesises lipids and steroid hormones
Rough ER is studded with ribosomes and is used for protein synthesis
17
Q
Golgi apparatus
A
- Consists of stacks of closely folded membranous sacs
* Proteins from Rough ER are packaged into secretory granules
18
Q
Lysomes
A
- Break down fragments of organelles and large molecules inside the cell
- Or in white blood cells ingest foreign material
19
Q
Cytoskeleton
A
- Consists of an extensive network of tiny protein fibres
- Microfilaments
- Microtubules
- Centrosome
- Cell Extensions
20
Q
Microfilaments
A
The smallest fibres, provide structural support and maintain shape of the cell
21
Q
Microtubules
A
Larger contractile protein fibres that move organelles in the cell, chromosomes during cell division and cell extensions
22
Q
Centrosome
A
This directs organisation of microtubules within the cell. It consists of a pair of centrioles and plays an important part during cell division
23
Q
Cell extensions
A
- Microvilli - tiny projections (greatly increase surface area)
- Cilia - hair like projections (beat in unison eg to move mucus upwards in the respiratory tract
- Flagella - single long whip projections
24
Q
Most body cells have 46 chromosomes and divide by
A
Mitosis - two new genetically identical daughter cells
25
The formation of gametes, ova and spermatozoa
Meiosis
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The period between two cell divisions is known as
The cell cycle
27
There are two phases of the cell cycle that can be seen on light microscopy
Mitosis (M phase)
| Interphase
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Interphase
Longer phase with three stages:
* First gap phase (G1) the cell grows in size and volume
* Synthesis of DNA (S phase) Chromosomes replicate forming two identical copies of DNA (96 chromosomes)
* Second gap phase (G2) further growth and preparation of cell division
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Mitosis
* Prophase
* Metaphase
* Anaphase
* Telophase
* Cytokinesis
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Prophase
The replicated chromatin become tightly coiled and easier to see. The chromosomes pair with its copy and are joined to each other at the centomere. Mitotic apparatus consists of two centrioles seperated by the mitotic spindle. The centrioles migrate one to each end of the cell and the nuclear envelope disappears.
31
Metaphase
The chromatids align on the centre of the spindle attached by the chromosomes
32
Anaphase
Cetromeres seperate and one pair of the sister chromatids migrate to each end of the spindle as the microtubules form the mitotic spindle
33
Telophase
The mitotic spindle disappears, the chromosomes uncoil and the nuclear envelope reforms.
34
Cytokinesis
The cytoplasm, intracellular organelles and plasma membrane split forming two identical daughter cells
35
Passive Transport
Substances move down concentration gradient without using energy
36
Facilitated diffusion
Passive process
| Specialised protein carrier molecules in the membrane assist substances across (lock and key - specific)
37
Osmosis
Movement of water down concentration gradient
38
Active transport
Transport of substances up the concentration gradient using the chemical energy ATP
39
Sodium Potassium Pump
Active transport mechanism maintains the unequal concentrations of sodium and potassium ions on either side of the plasma membrane
* Potassium levels higher inside
* Sodium levels higher on the outside
* 30% of cellar ATP requirements
40
Bulk transport
* Transfer of particles too large to cross cell membrane occurs by pinocytosis or phagocytosis - engulfed by cytoplasm
* Export of waste materials from the cell is called exocytosis
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Types of tissue
Epithelial, Connective, Muscle and Nervous tissue
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Epithelial Tissue is
A group of tissue found covering the body and lining the cavities, hollow organs and tubes.
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Epithelial tissue is for
Protection, secretion and absorption
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The cells are very closely packed and the intracellular substance is minimal
The matrix
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The cells usually lie on a
Basement membrane
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A single layer of cells
Simple epithelium
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Several layers of cells
Stratified epithelium
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Three types of Simple epithelium
Squamous, cuboidal and columnar epithelium
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Squamous epithelium lines these structures
Heart, blood vessels, lymph vessels, alveoli of the lungs, lining of the collecting ducts of nephrons in the kidneys. These are flat cells.
50
Cuboidal epithelium
It forms the kidney tubules and is involved in secretion, absorption and excretion. Cube shape
51
Columnar epithelium
Has adaptations such as cilia to aid in the movement of mucus in respiratory tract or ova are moved in the uterine tubes. Tall cells wth basal nuclei.
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Stratified squamous epithelium
Many layers that become flattened and then shed
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Keratinised stratified epithelium
Found on dry surfaces and provide a waterproof protective layer that prevents drying of live cells.
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Non keratinised epithelium
Where the internal cavity meets the external environment
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Transitional epithelium
This is composed of several layers of pear shaped cells. Found in the urinary bladder and allows for the stretching as the bladder fills
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Connective Tissue
Is the most abundant tissue in the body
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Function of connective tissue
Binding and structural support
Protection
Transport
Insulation
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Types of connective tissue (excluding blood)
Fibroblasts, Fat cells, Macrophages, Leukocytes, Plasma cells, Mast cells
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Fibroblasts
* Large cells with irregular processes.
* They produce collagen and elastin fibres
*Reticulin fibres
Tissue repair and granulation tissue
60
Fat cells
Adipocytes, vary in size and shape according to fat content
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Macrophages
* Irregular shaped cells with granules in the cytoplasm.
| * Aid defense mechanisms by engulfing and digesting foreign particles
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Leukocytes
White blood cells, found in small numbers in healthy tissue but are in vast numbers during infection.
63
Plasma cells
Develop from B-lymphocytes, they synthesise and secrete defence specific antibodies into the blood and tissue
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Mast cells
Similar to basophil leukocytes, and produce histamine and heparin.
Histamine for inflammation reactions
Heparin prevents coagulation of blood
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Loose (areolar) Connective tissue
The matrix is semi solid and many fibroblasts and some fat cells, mast cells and macrophages
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Loose (areolar) Connective tissue, connects and supports
Under the skin, between muscles, supporting blood vessels and nerves, alimentary canal and in glands supporting secretory cells
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Two types of Adipose tissue
White and brown adipose tissue
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Adipose tissue
consists of fat cells, (adipocytes),
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White adipose tissue
Makes up 20-25% of body weight (in well nourished adults - acts as a thermal insulator
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Brown adipose tissue
Present in the newborn
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Lymphoid tissue
Reticular cells and white blood cells (monocytes and lymphocytes)
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Dense connective tissue
Contain more fibres and fewer cells than loose connective tissue
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Fibrous tissue
Ligaments, Periosteum (outer covering for bone), Outer covering for some organs, muscle fascia, tendon
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Elastic tissue
Is capable of considerable extension and recoil. Few cells and matrix consists mainly of elastic fibres secreted by fibroblasts.
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Blood
Fluid connective tissue
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Cartilage
Firmer than other connective tissues, the cels are chondrocytes. Three types are:
* Hyaline cartilage,
* Fibrocartilage and
* Elastic fibrocartilage
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Hyaline Cartilage
Smooth blueish white tissue found on the ends of long bones, costal cartilage attach the ribs to the sternum and part of the larynx, trachea and bronchi
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Fibrocartilage
Dense masses of white collagen fibres:
Intervertebral discs
Semilunar Cartilages
Ligaments
79
Elastic Fibres
Flexible tissue consists of yellow elastic fibres lying in a solid matrix
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Bone cells
Osteocytes
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Muscle tissue
Able to contract and relax, providing movement within the body.
Skeletal muscle tissue
Smooth muscle tissue
Cardiac muscle tissue
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Skeletal muscle tissue
Voluntary and conscious control
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Smooth muscle tissue
Involuntary
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Cardiac muscle tissue
Muscle found round the heart wall and not under conscious control
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Nervous tissue
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Excitable cells (neurons) and
Non-excitable cells (glial cells)
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