Question

MCAT Tutorial: Introduction to Anatomy & Physiology

Answer 1

\({\bf{Basic~Terminology:}}\)
- anatomy: study of the structure of living matter
- physiology: study of how living matter functions
- tissues: groups of cells specialized to a function
- organ: 2+ tissue types combined to perform a higher function
- organ system: combination of organ and tissue types to perform a higher function

\({\bf{Types~of~Tissues:}}\): muscle, nervous, epithelial, connective

\({\bf{Muscle~Cells:}}\): makes up skeletal muscle, lines organ walls, pumps blood, thermoregulates
- contraction: ability to exert force
- extensibility: ability to be stretched
- elasticity: ability to return to the resting length after being stretched
- excitability: ability to propagate nerve impulse

Sub-types: skeletal, smooth, cardiac
- Skeletal: striated + voluntary; causes muscule movement/motion
- Cardiac: striated + involuntary; lines walls of the heart, pumps blood
- Smooth: unstriated, involuntary: lines blood vessels, moves nutrients/etc. through the body

\({\bf{Nerve~Cells:}}\) carry electrical impulses through the body
- sub-types: neurons and glial cells
- neuron: cell body (contains nucleus) + dendrite (reeives signal) + axon (transmit signals)
- glial cells: surround the neurons, can increase the speed of impulse, can provide nutrients

Answer 2

\({\bf{Epithelial~Tissue:}}\) line the body cavities/glands/walls, protect against friction and infection, secrete substances, detect environmental stimuli, derived from endoderm/ectoderm/mesoderm

subtypes: membranous (sheets of cells) and glandular (secretory cells)

1. high rate of regeneration
2. cellularity: high contact with other cells via tight junctions/desmosomes/adherens junctions
3. avuscularity: lack of blood vessels
4. polarity: division between apical surface (exposed to a cavity/lumen) and basal surface (attached to other cells), separated by tight junctions
5. basement membrane (basal lamina and reticular lamina)

Answer 3

\({\bf{Connective~Tissue:}}\)
- the most abundant tissue type
- support, protection, motion, transport, insulation, energy storage, communication
- originates from mesenchyme
- embedded in a secreted matrix

\({\bf{The~Extracellular~Matrix:}}\)
- ground substances made of collagen/elastin
- proteins, polysaccharides, glycoproteins
- proteoglycans: contain neg. GAG chains to trap positive ions/attract water
- fibronectin + integrin linkage: links the ECM and the cytoskeleton

fibers:
- white fibers: crossed linked collagen fibrils
- yellow fibers: elastin, provides flexibility, can be found in lungs/blood vessels/skin
- reticular fibers: thin collagen fibers, mesh structure

Types of Connective Tissue Cells & Their Functions
- fibroblast: connective tissue proper
- adipocytes: fat
- chondrocytes: cartilage
- osteocytes: bones
- white blood cells and macrophages: immune system
- mast cells: inflammatory response

Answer 4

Anyway, that's the end of my tutorial, I hope it was a helpful resource. Source material is the 2nd Edition Barron's Prep book for the new MCAT