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Simple Diffusion - gases and nonpolar compounds transport

By: HWC, Views: 7005

Gases and some molecules can diffuse through the phospholipid bilayer because they are small or non-polar. Oxygen gas. Carbon dioxide gas. Lipid based hormones. Plasma membranes are selectively permeable: The lipid bilayer is always permeable to small, nonpolar, uncharged molecules ...

Stroke volume

By: HWC, Views: 6665

Preload definition • Preload is the degree of stretch of cardiac muscles cells prior to contraction. • The amount of stretch is related to the end-diastolic volume[EDV]. • Increased return blood flow from the veins increases end-diastolic volume. Cardiac muscle sarcomeres stretch and ...

The Vestibular System

By: HWC, Views: 5946

The vestibular system has important sensory and motor functions, contributing to the perception of self-motion, head position, and spatial orientation relative to gravity. The function of the vestibular system can be simplified by remembering some basic terminology of classical mechanics. All ...

Import of Dietary Glucose from Intestines to Bloodstream

By: HWC, Views: 6123

• Membranes have hydrophobic interiors. which resist the passage of hydrophilic compounds and ions. • However. transporter membrane proteins facilitate the passage of these molecules. • Passive transporters accelerate diffusion of molecules towards equilibrium (decrease a concentrat...

Graded potentials - electrical characteristics and types

By: HWC, Views: 6946

• A graded potential occurs when a gated channel is opened or closed, altering ion flow through the membrane. • Changes in ion and charge distributions cause voltage changes to the resting membrane potential. • The strength of the stimulus determines the number of gated channels affect...

Stroke volume - contractility definition

By: HWC, Views: 6298

Contractility is the forcefulness of contraction of cardiac muscle. • Inotropic agents are substances that increase or decrease contractility (and stroke volume). • Positive inotropic agents increase contractility and will increase stroke volume and cardiac output. • Negative inotropi...

Bone processes - resorption and deposition, remodeling and response to stress in adult bones

By: HWC, Views: 6940

• The process of remodeling bone tissues involves bone cells resorbing or depositing minerals into bone tissue. • During resorption, bone cells break down bone tissue and release calcium and other minerals for use by other cells in the body. • Bone cells also rebuild bone tissue by depo...

Osmosis - water transport

By: HWC, Views: 6748

Osmosis is the flow of water down its concentration gradient, across a semi-permeable membrane. Osmosis is an example of diffusion, which is when molecules tend to distribute themselves evenly in a space. what is a semi-permeable membrane? It is a membrane or barrier that allows some molec...

Types of synapses - electrical & chemical

By: HWC, Views: 6717

• Neurons communicate with one another or effector cells via synapses that allow information to be filtered and integrated. • The two types of synapses are: • electrical • chemical. • Electrical synapses, also known as gap junctions, contain many ion channels (connexons) conne...