Tissues and homeostatis Flashcards by Haz ALL

Describe the order of organization

atomic
molecular
organelle
cell
tissue
organ
organ system
organism

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What are the 4 tissue types?

Muscular, connective, epithelial and nervous

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Describe the structure, importance and function of epithelial tissue

There are 2 types of epithelial tissue (stratified and simple)
Stratified refers to many layers whereas simple refers to a single layer of cells. Epithelial tissue is involved in protection, filtration, excretion, secretion, and absorption. It covers the organs and lines the blood vessels. 2 forms of epithelium glandular (secretion) and covering and lining (BV’s)

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What are the 4 shapes of the epithelial tissue

Columnar, cuboidal and squamous, these tissues all have differently shaped nuclei and are all attached to basement membranes

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Describe squamous epithelium

It is a single thin permeable flat layer of cells, normally found in places where diffusion is required e.g., alveoli. It contains disc-shaped nuclei & sparse cytoplasm. involved in filtration e.g., kidney, secretion. epithelium supported by a basement membrane

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Describe cuboidal epithelium

it is cube-shaped with a large central spherical nucleus, involved in secretion and filtration (kidneys), found in kidney tubules and ovaries

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Describe columnar epithelium

Highly specialized cells with oval nuclei, tall cells, found with goblet cells in the trachea, which secrete mucus, also found in digestive tract

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Describe pseudostratified columnar epithelial cells

These are single layers of cells that differ in height, and so the nuclei are at different levels to the adjacent cell, which may contain goblets cells and cilia. Involved in mucus secretion e.g., in digestion, the ciliated type propels the mucus in a direction.

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Describe the role of connective tissue

It’s main function is to support and bind the organs e.g., cartilage found in lungs

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What are the functions of connective tissue?

heat production, transport, binding of organs, immune protection, physical protection, support, storage, movement

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Describe the common characteristics of connective tissue

Connective tissue is the most abundant in the body, it has an extracellular matrix, which enables it to bear weight

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Give examples of connective tissues

Blood, cartilage, adipose tissue, elastic tissue, bone tissue etc

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What are the 3 main tissue types of connective tissue?

Areolar, adipose and dense connective tissue

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Describe areolar tissue

it has elastin and collagen fibres with a loose arrangement, it provides support, connects organs and tissues, and acts as cushioning and packing between organs. found beneath the skin surrounding organs and blood vessels, defends against infections

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Describe adipose tissue

This is fat tissue, involved in insulation, cushioning of organs & protection. Brown adipose in infants produces heat, contains lots of fatty acids, and is used for energy, 90% of mass in cells is adipose, richly supplied with nerve tissue

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Describe dense connective tissue

a dense tissue containing lots of collage fibres, irregular pattern, very strong and contain fibroblast nuclei. it creates fibrous coverings around organs and joints for protection

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Difference between clasts and blasts cells

Clast cells breakdown connective tissue
blast cells are mitotically active and secrete fiber and matrix

What is a lacuna

a space/cavity

what are the 3 types of cartilage?

hyaline cartilage, fibrocartilage and elastic cartilage

Describe hyaline cartilage

Most abundant in the body
involves in structural support and flexibility
Has spherical chondrocytes
Only fibre is collagen fibres
It covers the end of most movable joints (articular cartilage)
Connects the ribs to sternum (costal cartilage) aids in respiring
Supports the nose (nasal cartilages) and the respiratory system (respiratory cartilage)
Contain perichondrium which surrounds cartilage

Describe elastic cartilage

Contains more elastic fibres than hyaline cartilage
Able to stretch and recoil e.g., in blood vessels, prevents bursting from high BP
Are involved in repeated bending movements

Found only in external ear and epiglottis

Describe fibrocartilage

very fibrous lots of thick collagen fiber bundles, less matrix, fibers spread in all directions, resistant to impact, shock absorbent, found in knees and pubic bone
Consist of parallel rows of chondrocytes which alternate with thick collagen fibres

What are collagen fibres?

made of the protein collagen, assemble and cross-link together, and bundle together to form thick collagen fibres, due to linkage they are extremely strong, and tough and can resist being pulled apart

What are elastic fibres?

long & thin elastic fibres form branching networks, contain protein elastin, enabling stretch and recoil, found where elasticity is needed e.g., lungs and blood vessels

What is ground substance?

Known as the matrix contains proteins which trap water to make it a gel-like substance, site of protein synthesis and movement of organelles

Define Homeostasis

the ability to maintain an optimum internal environment within narrow limits, it is a dynamic equilibrium which is adapts due to changes in external environments

Examples of homeostatis

Temperature control- controlled by the hypothalamus, thermoreceptors on skin's surface can detect a stimulus (temp change) and sends signals to the hypothalamus for it to coordinate a response to bring body temperature back to optimum condition

Define negative feedback and give and example

Negative feedback is the most common homeostatic mechanism it prevents further deviation from optimum conditions e.g., sugar levels in the blood, need to be regulated, if too high, insulin is released storing excess glucose as fat, if too low glucagon is released to breakdown glycogen and release glucose into the bloodstream

Define positive feedback

This is when the response to the stimulus involves a greater deviation from set point, it is positive as it moves in the same direction and not a loop e.g., in labour, contractions are intensified by oxytocin as labour continues more oxytocin is released in increasing frequency and power of contractions. This continues until the baby is born

What is a cell

smallest functional unit of an organism

Purpose of nucleus

Holds DNA, controls activities of the cell

Purpose of plasma membrane

acts as a barrier, contains bulk of cell, involved in endo and exocytosis, controls what enters and exits cell

Cytoplasm function

gel-like substance, serves a site for enzyme reactions

What is chromatin

contains DNA, encodes the proteins, found in the nucleus

what is the nucleolus

involved in synthesis of ribosomes

What are ribosomes

responsible for making proteins through transcription and translation, ribosomes read RNA, cause AA's to bulk together and build proteins

What is RER

site of protein production,

what is the golgi apparatus>

site where protein is modified and packaged, becomes enzymes or glycoproteins

what is a vesicle

responsible for transporting proteins, can be exported outside of the cell via exocytosis

Cytoskeleton function

anchors organelles in place, provides a network in which vesicles travel along

SER

smooth endoplasmic reticulum involved in detoxfication, synthesis and packaging of lipids