Diversity and Function of Cells. Flashcards
What are the 4 basic tissue types?
- epithelium
- CT
- muscle
- nervous tissue
Define epithelial tissue
- cover surfaces of the body
- line hollow organs
- form many glands
- occur as sheets of cells
- vary wildly in size, shape, orientation and function
Define connective tissue
- forms framework of body
- dynamic role in the development, growth, homeostasis and energy storage
Define muscle
- specialised cells to generate force by contracting
Define nervous tissue
- neurons and supporting cells (glia)
- serve control function
- allow rapid communication between different parts of the body
What are the common features of epithelial tissue?
- strong adhesion between epithelial cells
- all have a layer of ECM called the basal lamina where the cells are attached
What are the major functions of epithelia?
- mechanical barrier (skin)
- chemical barrier (stomach lining)
- absorption via microvilli (intestinal lining)
- secretion (salivary glands)
- containment (bladder lining)
- locomotion via cilia (oviduct)
What are some minor functions of epithelia?
- sensation via neuroepithelium (taste buds)
- contractility (myoepithelial cells)
Define glandular epithelia.
epithelia that produces secretory products (sweat, milk, oil, hormones, mucous and enzymes)
Define endocrine glands.
- product secreted toward the basal end of the cell
- distributed by the vascular system
- ductless glands
Define exocrine glands
- product secreted toward apical end of the cell into the lumen of an internal space, duct or on the body surface
- ducted glands
What is a major characteristic of an endocrine gland?
- no ducts
- lots of capillaries
What is a major characteristic of an exocrine gland?
presence of ducts
What are the different classifications of connective tissue?
- soft connective tissue
- hard connective tissue
- blood and lymph
List some examples of soft CT
- tendons
- ligaments
- mesentery
- stroma of organs
- dermis
List some examples of hard CT
- bone
- cartilage
What is CT made up of?
- ecm
- cells
What are the components of ECM?
- fibres (collagen, reticular, elastic)
- ground substance (amorphous material made of GAGs)
- tissue fluid
What cell types are present in different CT?
- fibroblasts (maintain and produce ECM)
- adipose cells (fat cells)
- osteocytes (bone cells)
- chondrocytes (cartilage cells)
What are the defining characteristics of loose CT (soft)
- collagen fibres run in bundles
- collagen fibres don’t run parallel
- loosely packed fibres
- abundant ground substance
- relatively plentiful cells
What are the defining characteristics of dense regular CT
- collagen fibres run parallel and tightly packed
What are the defining characteristics of dense irregular CT
tightly packed irregular collagen fibres
What are the features of cartilage?
- strong
- flexible
- compressible
- semi rigid tissue
What causes cartilage to be semi-rigid?
highly hydrated nature of ground substance
Cartilage is avascular. How does it receive nutrients?
receives nutrients from adjacent tissues by diffusion through its matrix
What are the 3 types of cartilage?
- hyaline
- elastic
- fibrocartilage
What are the 2 types of bone?
- cortical
- trabecular
Describe the features of cortical bone
- dense bone
- forms outer shell
- makes up shaft
Describe the features of trabecular bone
- found in epiphyses of bone
- fine meshwork
- made up of trabeculae (bony spurs)
How is force produced by muscle contraction?
force produced by the movement of actin fibres of myosin fibres with the aid of a number of accessory proteins
What are the major muscle types?
- smooth muscle
- skeletal muscle
- cardiac muscle
What are the features of smooth muscle?
- most simple structure
- no visible striations
- predominantly found in organs
- not under conscious control
Describe smooth muscle cells
- elongated spindle shaped cells
- 20-200 micrometres
- cigar shaped nucleus near the centre
What are the features of skeletal muscle?
- multiple striations
- respond to conscious control
What are the features of skeletal muscle cells?
- giant
- multinucleated
- cylindrical cell
Where is cardiac muscle found?
- walls of heart chambers
- origins of great vessels
What are the features of cardiac muscle cells?
- single nucleus located at centre of the fibre\
- striations (less prominent)
- intercalated discs
What are intercalated discs?
sites of end to end attachment between fibres crossing at irregular intervals
What are the components of nervous tissue?
- neurons
- glial cells
What is the ratio glia to neurons in the CNS?
10 glia to 1 neuron
What is the name of the protective CT coat surrounding the CNS?
meninges
What is the name of the protective CT coat surrounding the PNS?
epineurium
What are the 3 types of neuron?
- multipolar
- bipolar
- pseudounipolar
What are the defining features of multipolar neurons?
- most common
- many dendrites
- one axon
What are the features of bipolar neurons?
- one dendrite
- one axon
what are the features of pseudounipolar neurons?
- short process extending from soma
- process gives rise to axons in both directions
List 3 principle glia of the CNS
- astrocytes
- oligodendrocytes
- microglia
What is the function of astrocytes in the CNS?
- support
- ion transport
- induction of the blood brain barrier
What is the function of oligodendrocytes in the CNS?
production of myelin in the brain and spinal cord
What is the function of microglia in the CNS?
immune surveillance
Name the principle glial cell of the PNS
Schwann cells
What is the function of Schwann cells?
- production of myelin in the PNS
- support axons in the PNS
