Lecture 6 Flashcards
Diencephalon
Diencephalon is deep within the brain, it composes the
walls of third ventricle
Diencephalon consists of
thalamus, hypothalamus, pituitary gland and pineal gland
Thalamus
Gateway to sensation
“Relay station and integrating centre” for preliminary processing of sensory afferent signals (what gets through, what doesn’t)
All sensory input (spinal cord, optic tract, cochlear tract) synapses here, are screened out and routed accordingly to cortex
Helps to direct attention to stimuli of interest (aircon noise, street noise etc filtered out)
Crude awareness of sensations (without location or intensity)
Positively reinforcing voluntary motor control
Hypothalamus
Collection of specific nuclei and associated fibers (less than 1% of total brain volume)
Integrating centre for homeostasis
Hypothalamus input
from reticular formation, cerebrum, sensory receptors
hypothalamus output
thalamus, multiple effector pathways
Hypothalamus links
autonomic nervous system with endocrine system
Hypothalamus controls
- body temperature
- Thirst and urine output
- Food intake/hunger
- Controls anterior pituitary hormone secretion
- Produces posterior pituitary hormones
- Directly regulating internal environment (eg shivering, vasoconstriction for heat homeostasis) Controls uterine contraction and milk ejection
- Autonomic nervous system: Smooth muscle, cardiac muscle, exocrine glands
- Emotion and behaviour
- Sleep/wake cycle
Upstream endocrine control
Upstream endocrine control: example cortisol
Thirst: Δ osmolarity and volume