+380.000 other summaries
A unique study tool
A rehearsal system for this summary
Studycoaching with videos
Remember faster, study better. Scientifically proven.
PREMIUM summaries are quality controlled, selected summaries prepared for you to help you achieve your study goals faster!
Summary - Mens en dierkunde II
1.1 Zoo Chptr 33: Nervous coordination
Difference nervous system vertebrate and bilateral invertebrates?
The nervous system of the vertebrates is hollow, dorsal and terminates anteriorly in a brain. Invertebrates have a solid nerve cord ventral to their alimentary canal (gut).
What is encephalization?
The evolutionary process of the elaboration of size, configuration and functional capacity of the brain.
Describe the human spinal cord.
Segmental nerves, 31 pairs, separated into dorsal sensory roots and ventral morot roots. Sensory nerve cell bodies are gathered together into dorsal root (spinal) ganglia. Both dorsal and ventral roots meet beyond the spinal cord to form a mixed spinal nerve.
The spinal cord encloses the spinal canal and all is wrapped in three layers of meninges. The two zones are the inner grey matter (containing cell bodies of motor neurons and interconnecting interneurons) and the outer white matter (containing bundels of axons and dendrites).
What is a reflex arc?
A unit of neural operation, usually consistant of 1) a receptor, 2) an afferent (or sensory neuron that carries signals towards the CNS), 3) the CNS, 4) an efferent (or motor neuron that carries the signals from the CNS and makes a synaptic connection with the interuneuron), 5) an effector (muscles, glands, cells..).
What is a reflex act?
A response to a stimulus ating over a reflex arc(s) (involuntary).
What are the three priciplal divisions of the early vertebrate brain?
prosencephalon (forbrain - smell), mesencephalon (midbrain - vision) and the rhombencephalon (hindbrain - hearing and balance)
What parts are located in the hindbrain and what do they do?
The medulla oblongata, together with the last part of the midbrain makes up the brainstem controlling vital and largely subconcious activities (heartbeat, respiration, vascular tone, gastric secretions..).
The pons, contains a thick bundle of fibers that carry impulses from one side of the cerebellum to the other and connects the cerebellum and medulla to other parts of the brain.
The cerebellum, dorsal to the medulla, controlls equilibrium, posture, and movement. It does not initiate movement but operates as a precision error-control center.
What is the midbrain responsable for and consist out of? Changed much over time?
Consists of the tectum (including the optic nuclei), which contains nuclei that serve as centers for visual and auditory rflexes. Changed in function not in shape.
What centers are found in the forbrain and where are they located?
The most posterior elements are the hypothalamus and the thalamus. The anterior portion of the forbrain (cerebrum) can be divided into the paleocortex (limbic system including the hippocampus) and the neocortex (cerebralcortex).
What do the thalamus and hypothalamus do?
Thalamus - relay station that analyzes and passes sensory information to higher brain centers.
Hypothalamus - homeostasis regulating centers. Also produces neurohormones and regulates reproduction and sexual behaviour and participates in emotional behaviour.
What do the neocortex and paleocortex regulate?
The paleocortex better known as the limbic system mediates several species specific behaviours that relate to sex and feeding (rhinencephalon/nose brain). The hippocampus related to learning and memory.
The neocortex/cerebralcortex regulates almost all intergrative activities and includes discrete moror and sensory areas (muscle movement and pressure, pain..). Vision, smell, hearing and speech. Association areas are also found, concerned with memory, judgement, reasoning..
What is the difference between the left and right side of the brain and how are they connected with eachother?
Connected by the corpus callosum, the left is responsable for language development, maths, learning and sequential thought processes and the right side is responsable for spatial, musical, artistic, intuitive and perceptual activities
1.2 Chptr 7: Mechanism of Behaviour
What is the nerve net and how does it work?
A net of nerves that are nonpolarized and conduct impulses in all directions. There is also no centralized processing of information, however simpel behaviours are still observed amoung the Cnidaria (sea anemones, hydra and jellyfish).
Peristaltic contraction in the gut wall of vertabrates is a nerve net. (& starfish back pincers)
What is the radially symmetrical nervous system?
The Echinodermata (starfish, sea urchin..) have a radially symmetrical nervous system. The nervous ring centered in the body leads out into nerve tracts extending into each arm. coodinated movements are partially controlled by impulses that travel through sensory neurons and interneurons, through the central ring, to motor neurons. Specialized types of receptors are found for receiving contact, taste, and general chemical signals.
What are bilaterally symmetrical nervous systems?
Found in animals with directional movement (worms, molluscs, arthropods (insects and crustaceans), and chordates. Associated with the evolution of a distinct head (cephalization). These animals became more specialized for movement, giving the ventral part of the body the side that was used for moving.
What are three characteristics of vertebrates due to the development of the vertebrate nervous system?
- Complexity of behaviour patterns and the general flexibility of behavioural responses are greater.
- Vertebrate responses are generally faster due to structure.
- Greater capacity of information storage.
Latest added flashcards
1. Ventricular filling (mid-to-late diastole)As the ventricles fill, the pulminary and aortic valves are closed. At the end of the phase the atria contract, driving more blood into the ventricles.
2. Isovolumetric contraction. The ventricles contract, which raises the pressure, the AV valves close and the semilunar valves stay closed because the pressure is not enough yet.
3. ventricular ejection.
4. Isovolumetric relaxation. The ventricles is relaxing, some blood is still present and it is still under pressure because it takes time for the muscle to wane. The pressure is too low to keep the semilunar open and too high to allow the AV valves to open.
The P waves is an upward deflection that is due to artrial depolarization. The QRS complex is a series of sharp upward and downward deflections due to ventricular depolarization. The t wave is an upward defletion caused by ventricular contractile cell action potential.
The p-Q or P-R interval is an estimate of conduction through the AV node.
The Q-T intercal is the time the ventricles are contracting.
The T-Q segment is an estimate of the time the ventricles are relaxing
The R-R interval is the time between heartbeats.
The AV can step up as a back up if the SA node would miss a beat or if the pathway was blocked.
If the AV node can't drive the ventricular contraction, the heart has another backup- certain cells in the Purkinje fibers (idioventricular pacemakers), eventhough they are slower.
The action potentials originating in the SA node travel through the AV node on their way to the ventricles, during this refractory period the cells cannot generate their own potential.
The second reason is that the SA node has a higher beat frequency, the SA node would always beat the AV node to the chase.
The AV can though step up as a back up if the SA node would miss a beat or if the pathway was blocked..