Module 1 - Biological Foundations Sept 11

Nervous Tissue Located in

• brain

• spinal cord

• nerves

Epithelial Tissue Located in

• lining of GI tract

• skin surface

Muscle Tissue Located in

• cardiac muscle

• smooth muscle

• skeletal muscle

Connective Tissue Located in

• fat and other soft tissue

• bone

• tendon

Four Types of Tissue

• nervous

• epithelial

• muscle

• connective

Nervous Tissue Key Functions

communicate and control

Muscle Tissue Key Function

force production

Connective Tissue Key Function

support/transmit force

Epithelial Tissue Key Function

covering/lining/exchange

Nervous Tissue Composed of

• neurons (receive and transmit info)

• neuroglia (support and maintain neurons)

Nervous Tissue found in the

• brain

• spinal cord

• peripheral nerves

Nervous Tissue Movement Connection

nervous tissue allows the body to sense —> integrate —> respond

Nervous Tissue - Sense

• detect changes in the environment

• sensory receptor detects a stimulus in the environment (eg., touch, stretch, pressure, temp, etc)

• sensory neuron (afferent) carries info towards CNS

Nervous Tissue - Integrate

• process and interpret info in the CNS

• CNS (brain and spinal cord)

Nervous Tissue - Respond

• send motor commands to muscles to produce movement

• motor neuron (efferent) carries motor commands away from CNS

• skeletal muscle - effector that contracts in response to neural command

Nervous Tissue - Movement

• coordinated muscle contraction produces movement

Nervous Tissue - Sense, Integrate, Respond steps

• sensory receptor detects stimuli

• afferent neuron carries info to CNS

• CNS processes info

• efferent carries motor commands away from CNS

• skeletal muscle contracts in response to motor commands

• movement occurs from muscle contraction

Muscle Tissue - Skeletal

• long, cylindrical fibres

• striated

• voluntary control

• moves the skeleton

Muscle Tissue - Cardiac

• branches cells

• striated

• involuntary control

• pumps blood

Muscle Tissue - Smooth

• spindle-shaped cells

• non-striated

• involuntary control

• moves/regulates contents through organs and vessels

Muscle Tissue - Movement Connection

• muscle tissue generates force to produce movement and support the physiological demands of movement

Connective Tissue - Specialized Cells

• fibroblasts

• osteocyte

• adipocyte

• red blood cell

Connective Tissue - Extracellular Matrix (ECM)

• fibres

• ground substance/fluid

Connective Tissue - Types

• loose connective tissue

• dense connective tissue

• specialized connective tissue

Connective Tissue - Loose Connective Tissue

• more ground substance and loosely arranged fibres

• areolar

• adipose

Connective Tissue - Areolar

• under skin and around organs

• wraps and connects structures

• provides support

Connective Tissue - Adipose

• adipocytes with relatively little matrix

• energy storage

• insulation

Connective Tissue - Dense Connective Tissue

• more densely packed fibres (mainly collagen)

• tendon/ligaments

Connective Tissue - Tendons/Ligaments

• dense collagen matrix

• transmits force

• stabilizes joints

• attaches muscle to bone (tendon) or bone to bone (ligament)

Connective Tissue - Specialized Connective Tissue

• unique matrix composition for specific functions

• cartilage

• bone

• blood

Connective Tissue - Cartilage

• firm, hydrated matrix

• cushions joints

• resists compression

Connective Tissue - Bone

• mineralized matrix

• support and leverage

• withstand mechanical load

• stores Ca2+

• contains blood forming cells

Connective Tissue - Blood

• delivers O2 and nutrients to working cells

• contributes to immune response

Epithelial Tissue Characteristics

• needed for protection, absorption, secretion, and exchange

• tightly packed cells forming continuous sheets

• covers surfaces and lines internal organs

• avascular

• rapidly regenerates

Epithelial Tissue - Movement Connection

• protects surfaces and regulates exchange between the body and its environment

Epithelial Tissue - Protect - Epidermis

• forms a barrier between body and environment

• stratified squamous epithelium

• protects body during movement

Epithelial Tissue - Exchange - Lungs

• regulates movement of substances into and out of the body

• simple squamous epithelium

• allows O2 and CO2 exchange to support energy production during exercise

Epithelial Tissue - Support Movement - GI Tract

• enables the functions that allow the body to perform and adapt to movement

• simple columnar epithelium

• allows nutrient and fluid absorption to fuel and support movement

Homeostasis

• dynamic regulation of the internal environment within normal physiological range

• regulatory systems act to keep them within ranges compatible with normal function

Homeostasis Examples

• glucose failure

• heat stroke - sweat to bring back down

• hypothermia - shiver to bring temp back up

Homeostatic Regulation

physiological adjustment to preserve homeostasis in variable environments

Homeostatic Regulation - Feedback Loop

• stimulus: change in environment

• receptor: sensitive to environmental change

• control centre: processes info from the receptor and sends out command

• effector: responds to command (either opposes or enhances stimulus)

Positive Feedback

• initial stimulus produces a response that exaggerates or enhances the change in the original conditions

• typically occurs when a potentially dangerous or stressful process must be completed quickly

• ex: childbirth

Negative Feedback

• effector opposes the original stimulus

• aims to minimize change and maintain normal range

• primary mechanisms of homeostatic regulation

• ex: blood pressure

Exercise Effects on Homeostasis

• ATP demand raises

• O2 demand raises

• CO2 production raises

• heat production raises

• muscle ion concentrations change

• fuel demands change

Exercising in the Cold

• exercise: heat production increases

• cold: heat loss increases

• body temp tends to fall

• body responds: skin blood flow decreases, shivering increases

Exercising in the Heat

• exercise: heat production increases

• hot: heat production increases, body temp rises

• body responds: skin blood flow increases, sweating increases, heat loss increases