A&P1 Ch. 12 Brain Regions & Structures

6 Brain Regions

• Cerebrum

• Cerebellum

• Diencephalon

• Brainstem: Midbrain

• Brainstem: Pons

• Brainstem: Medulla Oblongata

Midbrain

• associated with cranial nerves III - IV

• contains corpora quadrigemina

• contains substantia nigra

Corpora Quadrigemina

Response for reflexes involving sound and vision (startle reflexes)

Substantia Nigra

Controls muscle tone

• issues with this structure can cause tremors (Parkinson’s)

Diencephalon

• thalamus

• epithalamus

• hypothalamus

Thalamus

Relay center for sensory input

• ex: stimuli from the eye goes to the thalamus before occipital lobe

Epithalamus

Contains pineal gland

• this gland secretes melatonin — promotes sleep

Hypothalamus

• autonomic functions (heart rate, blood pressure, GI tract, respiratory rate)

• emotional responses — part of limbic system

• body temp.

• food intake — hunger, satiety

• water balance — thirst

• sleep/wake

• endocrine system — hormones

What connects the hypothalamus to the pituitary gland?

Infundibulum

Medulla Oblongata

• continuous with SC

• most inferior brain region

• associated with cranial nerves VIII - XII

Decussation of Pyramids

On anterior surface of medulla oblongata

• crossing of info between left and right sides of brain

• carries motor info (efferent)

• damage to left side of brain affects right side muscles (and vice versa)

Olives in Medulla Oblongata

Regions that help with balance and coordination

Medulla Oblongata Function

• coordination, balance

• heart rate, blood vessel diameter, respiratory rate, blood pressure, swallowing, vomiting, sneezing, coughing

Pons

• acts a bridge within brainstem and within cerebellum

• facilitates both afferent and efferent signals

• sleep cycles

• respiratory rate

• associated with cranial nerves V - VII