Biological foundations of psychology Dr. Amal Gamal Shehata Associate Professor RAK College of Dental Science VI Semester BDS 2011

At the end of lecture, the students should be able to know: What is Psychology? What is Psychobiology? the Nervous System & its Divisions.the Nervous System Central Nervous System Brain& spinal cord Peripheral Nervous SystemPeripheral Nervous System. Somatic Nervous System. Autonomic Nervous System (Sympathetic &Para sympathetic). Brain Structures /areas& functions.Brain Structures

Psychology as the study of Human behavior. What is Psychobiology? - In general: The study of the relationship between behavior and biological processes In particular: The study of the relationship between behavior and the brain

Psychobiology aims to get a more complete understanding of human behavior. All behavior results from biological processes.

Behavior = “The interaction of an organism with its environment. Three systems that interact with the environment : The immune system (protects the body) The endocrine system (maintains and regulates the body’s internal state) The nervous system (controls ongoing activity –biological basis of all ‘cognitive’ functions)

Divisions of the nervous system The nervous system can be divided into several connected systems that function together. The nervous system is divided into the central nervous system and peripheral nervous system.

Central Nervous System The central nervous system is divided into two parts: the brain and the spinal cord.

The brain and the spinal cord The average adult human brain weighs 1.3 to 1.4 kg (approximately 3 pounds). The brain contains about 100 billion nerve cells (neurons) and trillions of "support cells" called glia.nerve cells (neurons)glia The spinal cord is about 43 cm long in adult women and 45 cm long in adult men and weighs about grams.spinal cord The vertebral column, the collection of bones (back bone) that houses the spinal cord, is about 70 cm long. Therefore, the spinal cord is much shorter than the vertebral column.

Peripheral Nervous System The peripheral nervous system is divided into two major parts: the somatic nervous system and the autonomic nervous system.autonomic nervous system

Somatic Nervous System The somatic nervous system consists of peripheral nerve fibers that send sensory information to the central nervous system AND motor nerve fibers that project to skeletal muscle.

The picture shows the somatic motor system. The cell body is located in either the brain or spinal cord and projects directly to a skeletal muscle

Autonomic Nervous System The autonomic nervous system is divided into three parts: the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system.autonomic nervous system The autonomic nervous system controls smooth muscle of the viscera (internal organs) and glands.

This picture shows the general organization of the autonomic nervous system. The preganglionic neuron is located in either the brain or the spinal cord. This preganglionic neuron projects to an autonomic ganglion. The postganglionic neuron then projects to the target organ. (Notice that the somatic nervous system has only one neuron between the central nervous system and the target organ while the autonomic nervous system uses two neurons.)

The brain is divided into two halves, called hemispheres. Each hemisphere communicates with the other through the corpus callosum, a bundle of nerve fibers. corpus callosum Brain

Some differences between the peripheral nervous system (PNS) and the central nervous system (CNS 1.In the CNS, collections of neurons are called nuclei. In the PNS, collections of neurons are called ganglia. 2.In the CNS, collections of axons are called tracts. In the PNS, collections of axons are called nerves.

In the peripheral nervous system, neurons can be functionally divided in three ways: Sensory (afferent) - carry information INTO the central nervous system from sense organs or motor (efferent) - carry information away from the central nervous system (for muscle control). Cranial - connects the brain with the periphery or spinal - connects the spinal cord with the periphery. Somatic - connects the skin or muscle with the central nervous system or visceral - connects the internal organs with the central nervous system.

Brain areas.

Brain Structures/Cerebral Cortex The word "cortex" comes from the Latin word for "bark" (of a tree). This is because the cortex is a sheet of tissue that makes up the outer layer of the brain. The thickness of the cerebral cortex varies from 2 to 6 mm. The right and left sides of the cerebral cortex are connected by a thick band of nerve fibers called the "corpus callosum." A bump or bulge on the cortex is called a gyrus (the plural of the word gyrus is "gyri") and a groove is called a sulcus."corpus callosum."

Functions of Cerebral Cortex : Thought process. Voluntary movement. Language. Reasoning. Perception.

Brain Structures/ Cerebellum The word "cerebellum" comes from the Latin word for "little brain." The cerebellum is located behind the brain stem. In some ways, the cerebellum is similar to the cerebral cortex: the cerebellum is divided into hemispheres and has a cortex that surrounds these hemispheres.cerebellum

Functions of Cerebellum : Movement Balance Posture

Brain Structures Brain stem The brain stem is a general term for the area of the brain between the thalamus and spinal cord. Structures within the brain stem include the medulla, pons, tectum, reticular formation and tegmentum. Some of these areas are responsible for the most basic functions of life such as breathing, heart rate and blood pressure

Functions: Brain stem Breathing Heart Rate Blood Pressure

Hypothalamus The hypothalamus is composed of several different areas and is located at the base of the brain. Although it is the size of only a pea (about 1/300 of the total brain weight). the hypothalamus is responsible for some very important functions. One important function of the hypothalamus is the control of body temperature. The hypothalamus acts as a "thermostat" by sensing changes in body temperature and then sending signals to adjust the temperature. For example, if you are too hot, the hypothalamus detects this and then sends a signal to expand the capillaries in your skin. This causes blood to be cooled faster. The hypothalamus also controls the pituitary.

Functions: Hypothalamus Body Temperature Emotions Hunger Thirst Circadian Rhythms

Thalamus The thalamus receives sensory information and relays this information to the cerebral cortex. The cerebral cortex also sends information to the thalamus which then transmits this information to other areas of the brain and spinal cord.

Functions of Thalamus : Sensory processing Movement

limbic system The limbic system (or the limbic areas) is a group of structures that includes the amygdala, the hippocampus, mammillary bodies and cingulate gyrus. These areas are important for controlling the emotional response to a given situation. amygdala The hippocampus is also important for memory. Amygdala is' fear centre’ in the limbic system.

Functions of limbic system : Emotions Memory

Midbrain The midbrain includes structures such as the superior and inferior colliculi and red nucleus.

Functions of Midbrain Vision Audition Eye Movement Body Movement

summary Psychobiology is the study of the relationship between behavior and the brain Three systems that interact with the environment: The immune system, the endocrine system, and the endocrine system. The central nervous system is divided into two parts: the brain and the spinal cord. The peripheral nervous system is divided into two major parts: the somatic nervous system and the autonomic nervous system.autonomic nervous system The brain is divided into two halves, called hemispheres. Each hemisphere communicates with the other through the corpus callosum, a bundle of nerve fibers. corpus callosum

Brain areas, cortex is the outer layer of the brain, cerebellum which is divided into hemispheres and has a cortex that surrounds these hemispheres, The brain stem is a general term for the area of the brain between the thalamus and spinal cord, The hypothalamus is located at the base of the brain, The thalamus which send sensory information to the cerebral cortex which then transmits this information again to the thalamus. The limbic system is a group of structures that includes the Amygdala, the hippocampus, mammillary bodies and cingulated gyrus. cerebellum The midbrain includes structures such as the superior and inferior colliculi and red nucleus.

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