Cells & Tissues Flashcards

1
Q

Cytoskeleton

A

Microtubules: small tubular proteins which maintain cell structure and move organelles around the cell

Microfilaments: repeating units of actin, responsible for cell movement, changes in shape and make muscle contraction possible

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2
Q

Centrioles

A

A pair of organelles that organise microtubules during cell division to create spindle fibres

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3
Q

Cytoplasm

A

Viscous fluid containing proteins, other organic molecules and organelles

cytosol: where chemical reactions occur

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4
Q

Golgi apparatus

A

modifies and packages proteins.

made of flattened sacs called cisternae

contains enzymes that allow processing and excretion of lipids and proteins

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5
Q

Plasma membrane

A

a phospholipid bilayer that contains cholesterol, glycoproteins and glycolipids. it surrounds the cell and enables it to communicate and detect changes in the environment

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6
Q

Mitochondria

A

site of aerobic respiration - produces ATP
the most active cells have lots of mitochondria

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7
Q

What does catabolism mean

A

process of releasing energy

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8
Q

Nucleus

A

DNA is stored
Nuclear envelope: double membrane that separates the contents of the nucleus from the cytoplasm

Nuclear pores: gaps in nuclear envelope

nucleolus: produces ribosomes

DNA is stored as chromatin, but during cell division the chromatin forms distinct structures called chromosomes

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9
Q

Endoplasmic reticulum

A

RER: has ribosomes attached and is responsible for the synthesis of proteins

SER: synthesis and lipids and steroids. In muscle cells it releases calcium ions that trigger contraction

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10
Q

Ribosomes

A

Protein synthesis - attaches amino acids using. Ribosomes are composed of two subunits containing rRNA

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11
Q

Cilia

A

hairlike projections which allow movement of substances over the cell surface

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12
Q

Phospholipids

A

Hydrophilic heads and hydrophobic tails

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13
Q

What is the role of cholesterol in the plasma membrane?

A

stabilises the membrane

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14
Q

What is the role of channel proteins in the plasma membrane?

A

let larger molecules in - such as polar molecules

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15
Q

What is the role of receptor proteins in plasma membranes?

A

communicate with the environment outside the cell. molecules bind to them and a message is sent in. some have a carbohydrate molecule attached to them giving them immunological identity

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16
Q

Examples of passive processes in cells

A

simple diffusion
osmosis
facilitated diffusion

these do not require ATP as molecules move from a high concentration to a low concentration

17
Q

Examples of active processes in cells

A

Active transport
Endo/exocytosis

these require ATP as molecules move from a low concentration to a high concentration

18
Q

Types of cells in connective tissue

A

Fibroblasts: make collagen and elastic fibres.
Fat cells
Macrophages: important in the body’s defence mechanism since they are phagocytic
Leukocytes: WBC - Migrate in large numbers during infection
Mast cells: histamine is responsible for inflammatory responses and heparin prevents coagulation

19
Q

What are mast cells?

A

WBC that play a role in the body’s immune system and inflammatory responses

20
Q

Examples of connective tissue

A

Elastic tissue: allows considerable extension and recoil
Fibrous tissue: closely packed collagen, found in ligaments, periosteum, protective coverings
Hyaline Cartilage: chondrocytes arranged in small groups within cell nests and the bluish white matrix is solid

21
Q

Where is epithelial tissue found?

A

covering surfaces, lining cavities, forms glands

22
Q

Simple epithelium

A

single layer of cells.

squamous epithelium: single layer of flattened cells, found in endocardium, alveoli and collecting ducts

Cuboidal epithelium: forms walls of kidney tubules and is found in the thyroid gland

Columnar epithelium: single layer of tall and thin cells on a basement membrane. Found in the stomach, small intestine and trachea

23
Q

Stratified epithelium overview

A

several layers of cells of various shapes
continual cell division in the lower layers pushes cells nearer to the surface. main function is to protect underlying structures from wear and tear.

24
Q

stratified squamous epithelium

A

in the deepest layers the cells are mainly columnar
keratinised: dry surfaces. no nuclei. provides tough and waterproof layer

non-keratinised: protects moist surfaces

25
Transitional epithelium
pear shaped cells that allow stretching present in the urinary tract
26
Skeletal muscle
moves bones striated and is under voluntary control fibres are cylindrical and contain multiple nuclei
27
Smooth muscle
non striated and involuntary has lots of mitochondria regulates the diameter of blood vessels
28
Cardiac muscle
not under conscious control striated each fibre has one nucleus intercalated discs are significant for heart contraction
29
Types of nervous tissue
Excitable: neurones which initiate, receive, conduct and transmit info non excitable: glial cells which support neurones
30
3 types of membranes
Cutaneous Mucous Serous
31
Mucous membranes
Lines hollow organs lines the alimentary, respiratory and genitourinary tracts epithelial cells secret mucus - which protects the membranes from drying
32
Serous membranes
Closed cavities double layer of loose areolar connective tissue lined by simple squamous epithelium parietal = lines a cavity Visceral = surrounds an organ
33
cell cycle overview
Interphase: growth and replication Prophase: chromatin condenses and becomes visible. spindle fibres form, centrioles go to opposite poles Metaphase: chromosomes line up on the metaphase plate attached by their centromeres Anaphase: centromeres become separated, one of each pair of chromatids migrate to each end of the cell. spindle fibres shorten Telophase: spindle fibres disappear, chromosomes decondense, plasma membrane splits
34
Apoptosis
genetically programmed cell death. shrinks and remaining fragments are phagocytosed without an inflammatory reaction
35
Necrosis
Cell death as a result of lack of oxygen due to injury or pathological process
36
Common causes of tumours
spontaneous changes in DNA or exposure to carcinogens such as: chemicals, ionising radiation and oncogenic viruses
37
3 ways in which tumours can spread
Local spread: benign tumours grow and cause pressure damage Lymphatic spread: group of tumour cells can break off and be carried to lymph nodes where they may lodge into secondary tumours, this may cause further spread into the lymphatic system because lymph drains into subclavian veins Blood spread: thrombus may form, blocking blood vessels causing infarcts and the development of metastatic tumours
38
Effects of tumours
Pressure effects: compression of adjacent structures can cause ischaemia, necrosis, blockage of ducts and pain Hormonal effects: well differentiated tumours can secrete uncharacteristic hormones such as lung tumours secreting insulin Cachexia: severe weight loss, weakness and lack of appetite
39
Common causes of death in malignant disease
Infection: predisposition of infection is increased by prolonged immobility or bedrest and due to chemo or radioactivity Organ failure Carcinomatosis: widespread metastatic disease Haemorrhage: Tumour ruptures