A.2 Flashcards
Hypothalamus
Maintains homeostasis, coordinating the nervous and endocrine systems. It synthesizes hormones stored in the posterior pituitary and releases factors regulating the anterior pituitary.
Cerebral hemisphere
Integrating center for higher complex functions like learning, memory, emotion
Cerebellum
“Little brain” with 2 hemispheres and a highly Folded surface. It coodinates unconscious functions like movement and balance
Medulla oblongata
Controls automatic and homeostatic activities like swallowing, digestion, vomiting, beathing, heart activity
Pituitary gland
Two lobes: posterior and anterior which secrete hormones regulating many body functions and are controlled by hypothalamus
Swallowing center
In medulla oblongata, coordinates muscles of the mouth to make food go down oesophagus
Cardioinhibitory center
Heart rate will slow down, when you first begin to exercise
Cardioaccelerater center
Heart rate speeds up for strenuous exercise
How do we know about the brain
- Animal experimentation –> causes of behaviour
- fMRI: brain scans revealed effect of addicting drugs
- human injuries: lesions shows differences in two halves
- ct scan:
Corpus colossum
Thick band of axons that connect the two hemispheres of the brain and allow communication made of white matter
Lesions
Areas of damage or tissue death
Autopsy
Used to find broca’s area
The peripheral system
Other parts of the neevous system that has 2 parts: somatic system and autonomic system
Central nervous system
Consists of the brain and spinal chord
Somatic system
Information received by the senses and messages sent to the skeletal muscles
Autonomic system
Controls cardiac muscle of heart, smooth muscle, and glands, consists of 2 systems that are antagonistic
Parasympathetic system
Important in returning to normal
Response is to relax
Neurotransmitter: acetylcholine
Inhibitory
Sympathetic
Important in an emergency
Response to fight and flight
Neurotransmitter: noradrenaline
Excitatory
The pupil reflex
Pupil closes in response to sudden input of light, cranial reflex –> sensory and motor neurons connect to the brain instead of spinal chord
Closes as a result of a parasympathetic response
Atropine drug used to stop acetylcholine
Iris
Surrounds the opening over the lens called the pupil and contains 2 smooth muscles to open and close the pupil
Circular and radial muscle
Circular muscle contracts and radial muscle relaxes as a result of the pupil consticting
The pupil reflex (process)
Optic nerve receives messages from retinaat back of eye, it contain photoreceptors that receive stimulus of light, synapse with bipolar neurone and ganglion cell. Nerve fibres of ganglion cell become optic nerve. The optic nerve connects with the pretectal nucleus if the brainstem
Brainstem
Controls heart rate, breathing rate, blood flow to the digestive system
Brain death
When there is no movement of extremities (arms legs fall), eye (remain fix, lack of brain to motor reflex –> no rolling of eyes as head turns) cornea relfex( cotton tige on cornea no blinking) pupil reflex (no constriction) gag reflex, respiration. There can still be spinal reflexes
Test used for brain death
EEG and CBF
Cerebrum
Develops from the front part of the neural tube, largest part of the brain
Cerebral cortex
A thin layer of grey matter (unmyelinated neurones) covering the cerebrum contains 75% of body’s neurones
Body size and brain size correlation
Human brain larger in proportion to other animals
E: S ratio where E is brain weight, S brain weight
Larger animal is smaller ratio
Eq ratio between actual brain size and predicted brain mass of an animal
Differences in cerebral cortex of humans and animals
Human brains have larger surface area, in amouse it is smooth. Human brain folds to fit in skull, more surface area for higher complex behaviours
Nucleus accumbens
Associated with reward circuit responds to dopamine, promotes desire –> activated: anticipation of reward, drugs like cocaine increase it
and serotonin inhibits desire (neurotransmitters)
Visual cortex
Part of brain that receives information from the cells in the retina, cooperates to produce vision
Left and right hemisphere
The left cerebral hemisphere receives sensory inout from sensory receptors on right side of body and right side of visual field in both eyes and vice versa
Primary somatosensory cortex
The main area for receiving sense of touch
Sensory input from right hand sent to left primary sensory somatosensory cortex
Motor cortex
Controls voluntary movements right cerebral hemispheres controls left motor cortex vise versa
Strokes
Blockade or ruptured blood vessel that interupts oxygen flow. Plasticity allows other brain parts to take control
Neurones
High energy need always in a state of high metablic activity. Neurones relair and rebuild like other cells, but chemical signals that communicate between neurones consume half energy used by brain
Glucose
fuels metabolism of neurones, constant supply not stored in neurones, used rapidly during mental activity supplied by carbohydrates : fruits vegetables grains dairy
Study on rates –> older glucose runs out quicker to area of learning and memory
