Week 4: Diencephalon & Brain stem Flashcards
The diencephalon occupies the …… part of the brain
Central
The diencephalon is nestled under in between the …… hemisphere and is located …… to the brainstem
Cerebral
Superiorly
Function of the diencephalon
Relays sensory information between brain regions & controls many autonomic functions of the PNS
Several structures of the diencephalon work together and with our body parts to affect the following bodily functions:
- Sensation impulses
- Autonomic regulation
- Endocrine function
- motor function
- Bodily homeostasis
- Taste
- Smell
- Vision
- Hearing
- Touch perception
The diencephalon is directly responsible for connecting the parts of ….. glands
Secretion glands
ie connecting the endocrine system with the nervous system
The diencephalon is also connected with the …… lobe. In particular it helps us manage ……
Limbic
Memories (and emotions)
What are the four elements of the diencephalon?
Thalamus
Hypothalamus
Epithalamus
Subthalamus
The thalamus is a large egg shaped mass of …… matter
Its located deep in the ….. just above the ……
1 thalamus is present on each side of the …… ventricle
It resembles a ….. and is ….. centimetres long …… centimetres high and ….. centimetres wide
Part of the brain where ….. information from all over the body ……
Sensory information synapses with neurons in the thalamus send signals to the ……… for processing
It also helps the ….. cortex organised coordinated ….. movements
- Grey
- Forebrain & midbrain
- Third
- Walnut, 3cm long, 2.5cm high, 2cm wide
- Sensory & converges
- Cerebral cortex
- Motor & voluntary
Upper vs lower part of the thalamus
The upper part of the thalamus transfers info & processes info from majority of the sensory organs/receptors to the cerebrum
The bottom part contains centres that regulate things such as body temperature feelings of hunger, satiety and thirst
The hypothalamus is located in the ….. of the base of the brain and encapsulates the ventral portion of the ….. ventricle
The hypothalamus has a close link with the …… gland which is an area that controls all glands in the endocrine system
This is why we say that this particular part of the diencephalon is the …… between the CNS and the endocrine system
Some of the physiological processes that are regulated by the hypothalamus include things like ……
The hypothalamus is part of the …… system so it also influences various ….. responses . It does this through its connections with the pituitary gland skeletal muscular system and our autonomic nervous system
- Middle & third
- Pituitary
- Bridge
- Body temperature, fluid balance, electrolyte balance, cardiovascular system functioning and blood pressure
- Limbic & emotional
What three sections make up the brainstem?
*From superior to inferior
Midbrain
Pons
Medulla oblongata
The grey matter within the brain stem consists of …….
It forms many important brainstem ….. which are a collection of nerve cell bodies
Nerve cell bodies
Nuclei
….. of 12 cranial nerves arise from nuclei in the brain stem
10
The midbrain is the most ….. part of the brainstem
It is the smallest/biggest section of the brain stem and is situated just above the ….
It contains numerous ……. that have a key role in connecting the cerebellum & cerebrum as well as other brain areas
Its main function is …….
It includes the nuclei of the ….. cranial nerves
- Superior
- Smallest & pons
- Nerve tracks
- Visual auditory and movement & control
- 3rd, 4th & 5th
There are many important brain structures in the midbrain - two of these are the …..
Four others include the…..
Tectum & Tegmentum
Other than these two there are four other crucial midbrain structures including the substantia niagara, cranial nerves, the cerebral peduncle and cross cerebra (3 & 4 are not covered)
What makes up the tectum?
The four colliculi (2 superior & 2 inferior). These are four prominent rounded elevations.
Role of the superior colliculli vs inferior colliculli of the tectum?
The superior colliculi = visual reflex centres - helps us visually track moving objects/control reflexes in response to visual stimuli
The inferior colliculi are out auditory reflex centres and control reflex of responses to sound
What is the tegmentum?
The tegmentum stretches down the length of the brainstem however a small portion of the tegmentum forms part of the midbrain
What are the 3 distinct areas of the tegmentum? What are their roles?
Named after their specific colours the first is the iron rich red nucleus which is involved in the coordination of movements, next we have the substantial Niagara which contains dark pigmented dopamine neurons these are important for the regulation of movements. Finally we have the periaqueductal grey matter - this is a dense region of grey matter that is involved in suppressing pain
What in the tegmentum is a dense region of grey matter responsible for suppressing pain?
Periaqueductal grey matter
The tegmentum and midbrain also contain connections that play a role in keeping us alert? True or False
True
The pons is one of the ….. parts of the brain at only ….. in length.
It is …. to the midbrain and ….. to the medulla
Smallest & 2.5cm
Inferior and superior
What is the portion of the brainstem through which all info that travels throughout the nervous system must pass at some point
Pons
In Latin pons = bridge - refers to the fact that the pons connects the cerebral cortex to the medulla by the cerebral peduncles. True or false.
True
The pons is involved in many autonomic and sensory functions including….
Arousal, fine motor control, muscle tone, respiratory processes, equilibrium and the circadian cycle specifically regulating our sleep
What are the four main nerve tracts that pass through the pons to control sensory autonomic involuntary functions of the body
These are the corticospinal tract, corticobulbar tract, the medial lemeniscus tract and the spinothalamic tract
The medulla is an elongated section of ……. tissue that makes up a part of the brainstem that connects to the spinal cord
It is actually …….. with the spinal cord meaning there is not a clear delineation between the spinal cord and the medulla but rather the medulla gradually transitions into the spinal cord
The medulla is ….. in shape and measures …. centimetres in length and … centimetres at its widest point
- Neural
- Continuous
- Conical, 3cm & 2cm
Responsibilities of the medulla?
The medulla is responsible for regulating many basic functions of the autonomic nervous system including respiration, cardiac function, vasodilation and many reflexes such as coughing, swallowing, sneezing and vomiting
The cerebellum is the ….. part of the hindbrain and is located in the ….. ….. ….. behind the ….. ventricle …. & ….
Largest
Posterior cranial fossa
4th ventricle, pons & medulla
…… …… (an extension of the dura matter) separates the cerebellum (occipital lobe) from the cerebrum
Tentorium cerebelli
The cerebellum consists of two hemispheres joined by the …..
Vermis
What are the three lobes of the cerebellum
The anterior lobe, the posterior lobe and the floccule nodular lobe
The cerebellum is extremely neuron rich containing ….% of the brains neurons
80%
Role of the cerebellum?
It plays a role in motor movement regulation and balance control
The cerebellum also coordinates gait and posture, controls muscle tone and involuntary muscle activity
Despite this the cerebellum is unable to initiate muscle contraction or initiate movement
Therefore with cerebellar damage you can still perform movements but you will lose the things such as the ability to control fine motor movements and maintain posture IE people will lose their balance
