Psychology is eh study of the mind, mental processes and emotions especially in relation to behaviour.
Biological psychology
Different aspects of behaviour exist: * Physiological: relating to the activity, the function of the brain ans other organs. * Developmental: tracing how genes, nutrition and experiences influence behaviour. * Evolutionary: showing how certain behavioural patterns which evolved in our remote ancestors are inherited. * Functional: showing how he inherited behaviour is advantageous because of the useful function it serves.
The Human Body * A complex organism made up of many systems. * Acts as a coordinated controlled unit. * It is the function of the Nervous and the Endocrine Systems to act as the coordinator of this controlled unit.
The Nervous System and The Endocrine System * Both control and coordinate body activities. * Work separately and in different ways but are liked by the pituitary gland (the master gland) and the hypothalamus (part of the brain). * The hypothalamus regulates the functioning of the pituitary gland by monitoring the levels of the hormone in the blood. * The nervous system consists of: 1. The central nervous system (CNS): brain + spinal cord. 2. The peripheral nervous system (PNS): the somatic nervous system (voluntary) + the autonomic nervous system (involuntary). The autonomic nervous system consists of the sympathetic system (flight/fight action) + the parasympathetic system (relaxation).
The Nervous System Function * Transmits information from the environment to the body or from one part of the body to the other through a network of specialised cells called neurons connected to all parts of the body. * Stimuli (messages) are received by sensory neurons, they are passed on to motor neurons (the effectors), which stimulate the proper organ/s or muscles to react appropriately to the original stimulus.
Cells of the Nervous System: Neurons
Contain all the components of a typical cell plus special branchlike additions to help make communication between neurons more efficient. Three types: 1. Sensory cells: receive messages, stimuli (afferent impulse) from the internal and external environment and pass them on from the PNS to the CNS. 2. Motor cells: transmit the impulse from the CNS to the appropriate organ/s, glands and muscles which react to the original stimulus (efferent nerve impulse). 3. Local neurons (interneurons): short axon neurons that connect sensory neurons to motor neurons.
Cells of the Nervous System: Glial Cells * Smaller and more numerous than neurons. * How no axons or dendrites. * Do not transmit information along long distances. * Provide support and protection for neurons: 1. Surround neurons + hold them in place + insulate them. 2. Supply nutrients and oxygen to neurons. 3. Destroy pathogens. 4. Remove waste material.
The Endocrine System
Made up of ductless glands, located in various parts of the body, which produce chemical compounds (mainly proteins) called hormones.
Hormones are: * Chemical messengers secreted by the glands directly into the bloodstream and carried by the blood to the target organs (specific site where the hormones act). * Present in small quantities but are very effective in controlling and coordinating many body activities such as metabolism and growth. * Recognised by and joined to specific receptors on cell membranes of the target organ, they combine forming a hormone-receptor complex and pass into the cell, influencing a particular reaction within the cell.
The Structure of the Animal Cell * Bound by a semi-permeable membrane: separates the inside of the cell from its outer environment and controls what goes in/out of the cell. * The cytoplasm; the site where most cellular activities take place. It is composed of the cytosol and organelles. The cytosol is a jellylike substance, mainly water with salts, organic molecules and enzymes. Also includes the cytoskeleton, made up of protein microtubules that give the cell its shape and help in the movement of substance within the cell. Organelles are different structures within the cytoplasm. * The nucleus is the largest organelle found in the cytoplasm. It has a double membrane and contains the genome of the organisms (hereditary factors). The nucleus controls the activities of the cell.
The Organelles of an Animal Cell: Mitochondria * Found suspended in the cytosol of the cytoplasm. * Present in all cells, especially in cells that are very active and need energy (muscle cells). * Usually rod-shaped. * Have a double membrane, the outer one is smooth and surrounds the mitochondrion, whilst the inner membrane forms folds called cristae. * The site of the aerobic stage of respiration, forming ATP molecules. The Organelles of an Animal Cell: Ribosomes * Minute structures built in two subunits. * Not bound by membranes. * Site of protein synthesis. * Some are free in the cytoplasm. * Some are attached to endoplasmic reticulum forming the rough endoplasmic reticulum (RER). Endoplasmic Reticulum * Network of tubules, vesicles and sacs: Interconnected and surrounded by membrane. * Smooth Endoplasmic Reticulum (SER): has no ribosomes attached to the surface. Transports proteins to other locations. Inserts proteins into cell membranes. Synthesises steroids and lipids. Stores calcium in some cells. * Rough Endoplasmic Reticulum (RER): has ribosomes attached to the surface. Transports protein synthesised in ribosomes to Golgi bodies for secretory packaging.
Golgi bodies * Present in all cells and develop from outer membrane of the nucleus. * Consist of stacks of flattened membranous sacs. * Modify hormones, enzymes, polysaccharides and lipids. Packed in vesicles and secreted when needed. * Vesicles develop from Golgi bodies into lysosomes and secretory vesicles. The Plasma Membrane Structure * Forms a barrier between the cell content and the environment. * It is semi-permeable about 8nm thick. * It is a phospholipid bilayer: hydrophilic heads (attract water), made up of Glycerol molecule + ionised phosphate group (polar) AND hydrophilic tails (repel water), made up of 2 fatty acids molecules. * Studded with globular proteins. Some across the bilayer, some on one side of the membrane.
The Plasma Membrane: A Fluid Mosaic Model * Fluid as the fatty cells (tails), are always moving cholesterol molecules found between fatty acid tails restrict movement, the it becomes less fluid allowing fewer molecules through it. * The scattered proteins within the bilayer giver it a patchy, mosaic look. * On the outer side of the membrane polysaccharides joining to proteins and lipids forming glycoproteins and glycolipids. These glycoproteins act as recognition and receptor sites. Receptors enable hormones and neurotransmitters to bind to specific cells. The Plasma membrane: membrane proteins * Carriers: for water-soluble molecules (glucose in facilitated diffusion). * Gated Channels: for ions such as Sodium Chloride. * Pumps: use energy to move water-soluble molecules or ions. * Receptors: allow substances such as hormones and neurotransmitters to bind to the membrane. * Enzymes: speed up chemical reactions at the edge of the membrane. * Adhesion sites: help cells to tick together forming the various tissues. The Plasma membrane: movement of substances in and out of cells * The membrane is selectively permeable. * All transport of substances in and out of cells occur in solution. * Transport takes place by: 1. Diffusion (passive) of by facilitated diffusion (glucose). 2. Osmoses (passive). 3. Active Transport (active needs energy that is ATP). 4. Bulk Transport of solid or liquid substances by means of vesicles. The flexibility of the membrane makes this movement possible. Energy (ATP) is required.
