sl integration of body systems Flashcards
System integration
- This is a necessary process in living systems. Coordination is needed for component parts of a system to collectively perform an overall function.
The spinal cord as an integrating centre for unconscious processes
- Students should understand the difference between conscious and unconscious processes.
Integration system for unconscious processes.
Carries nerve impulses between the brain and the rest of the body.
Controls reflexes (e.g. pain reflex) without input from the brain.
Reflexes are unconcious, automatic and involuntary
Cells, tissues, organs and body systems as a hierarchy of subsystems that are integrated in a multicellular living organism
- Students should appreciate that this integration is responsible for emergent properties. For example, a cheetah becomes an effective predator by integration of its body systems.
OSSD - target cells
Target cells contain receptor proteins that are specific to each hormone.
When a hormone binds to its receptor it triggers a reaction inside the cell
There are two types of hormones
Steroid Hormones
These are made from cholesterol, are lipid soluble and can easily diffuse through the cell membrane.
Testosterone, estrogen, cortisol steroid hormones
Protein Hormones
These are water soluble hormones, such as amino acid based hormones and cannot diffuse across the cell membrane
They bind to a receptor on the outside of the cell and triggers a chain reaction inside.
Activates an enzyme inside the cell to convert ATP to cyclic adenosine monophosphate (cAMP). This triggers more reactions.
Once the hormone’s message has been delivered, it is broken down
Insulin and GH secondary messenger
Integration of organs in animal bodies by hormonal and nervous signalling and by transport of materials and energy
- Distinguish between the roles of the nervous system and endocrine system in sending messages.
- Using examples, emphasize the role of the blood system in transporting materials between organs.
Control of the endocrine system by the hypothalamus and pituitary gland
- Students should have a general understanding, but are not required to know differences between mechanisms used in the anterior and posterior pituitary.
Modulation of sleep patterns by melatonin secretion as a part of circadian rhythms
- Students should understand the diurnal pattern of melatonin secretion by the pineal gland and how it helps to establish a cycle of sleeping and waking.
- Circadian rhythms are controlled by a ‘biological clock’ within the brain. This rhythm is a 24-hour cycle & continues even if a person is placed experimentally in continuous light or darkness. This rhythm is controlled by melatonin.
- Circadian rhythms depend on the suprachiasmatic nuclei (SNC)
effects of melatonin
- sleep/wake cycle
- regulates hormone release
- antioxidant
- inhibits release of insulin
-protects skin cells
Epinephrine (adrenaline) secretion by the adrenal glands to prepare the body for vigorous activity
- Consider the widespread effects of epinephrine in the body and how these effects facilitate intense muscle contraction.
The brain as a central information integration organ
- Limit to the role of the brain in processing information combined from several inputs and in learning and memory.
- Students are not required to know details such as the role of slow-acting neurotransmitters.
Central information integration organ
Receives impulses from sensory receptors
Integrates information
Sends impulses to effector organs
Stores information and forms memory.
Coordinates conscious, voluntary functions.
Initiates impulses
Seat of personality and emotions
brain
Information received by the brain comes from sensory receptors (e.g. photoreceptor in the retina of the eye).
The information is processed, stored (memory), and instructions are sent out.
Signals are then sent out along motor neurons to muscles or glands, which execute the instructions.
Learning and memory are formed in…
Information that is processed by the brain is usually….
the cerebrum and its cerebral hemispheres - the large folded part of the brain.
conscious – it happens at an awake state of mind.
Role of the cerebellum in coordinating skeletal muscle contraction and balance
- Limit to a general understanding of the role of the cerebellum in the overall control of movements of the body.
The cerebellum controls balance and muscle contraction. It fine-tunes and coordinates the timing of contractions.
The cerebellum helps us to keep balance, but also is involved in the formation of muscle memory.
Input to the spinal cord and cerebral hemispheres through sensory neurons
- Students should understand that sensory neurons convey messages from receptor cells to the central nervous system.
- Electrical impulses pass from receptors to the CNS along sensory neurons, synapse with interneurons which send electrical impulses along motor neurons to effectors.
- Sensory receptors or free nerve endings located in the skin and sense organs perceive changes in the environment. The stimulus is passed on to sensory neurons which convey it to the CNS in form of nerve impulses carried along the axons fibres.
Input to the spinal cord and cerebral hemispheres through sensory neurons
- The rod and cone cells in the retina of the eye receive light in form of electromagnetic waves as a stimulus. The signal is transmitted to the visual cortex in the cerebral hemisphere.
Tiny hair cells embeded within a fluid in the cochlea of the ear act as mechanoreceptors responding to soundwaves which are transported through the fluid. Processing of sound occurs in the auditory cortex.
- A number of different touch receptors in the skin respond to different stimuli such as pressure, pain or temperature.
- These chemoreceptors in form of free nerve endings receive airborne chemicals as a stimulus.
- Taste receptors embedded within the tissue of the tongue act as chemoreceptor, binding to food chemicals as a stimulus.
