Passive and Active Transport Prof. Sahar El Agaty| Professor of Physiology Biophysics -Physiology Lecture 3

Dr. Azza Hamed AbdElwahab Professor of Medical Physiology.

[Audio] Our body is made up of two main types of systems, the voluntary and involuntary systems. The involuntary system includes the autonomic nervous system, which has two branches, the sympathetic and parasympathetic nervous systems. The sympathetic nervous system is responsible for the fight or flight response, preparing the body to respond to stress or danger. It increases heart rate, blood pressure, and respiration rate, and also increases the release of glucose from stored energy sources. We can see this system at work when we are faced with a situation that requires immediate action, such as running away from a threat. The sympathetic nervous system is often referred to as the adrenaline response because it triggers the release of adrenaline, also known as epinephrine. This hormone helps to prepare the body for action by increasing heart rate, blood pressure, and respiration rate, and also increases the release of glucose from stored energy sources. The sympathetic nervous system plays a crucial role in our daily lives, helping us to respond to situations that require quick action. It is also involved in other processes such as regulating body temperature, and aiding in the digestion process. We will explore the parasympathetic nervous system in our next lecture. We can see the sympathetic nervous system at work in various physiological processes, and it is an essential component of our autonomic nervous system. It is also known as the adrenaline response because it triggers the release of adrenaline, also known as epinephrine. We will continue to discuss the sympathetic nervous system and its functions in this lecture. We will also explore the differences between the sympathetic and parasympathetic nervous systems. We will see how the sympathetic nervous system helps us to respond to stress or danger, and how it prepares the body for action. We will also discuss how the sympathetic nervous system is involved in regulating body temperature, and aiding in the digestion process. We will explore the role of the sympathetic nervous system in our daily lives, and how it helps us to respond to situations that require quick action. We will also see how the sympathetic nervous system is an essential component of our autonomic nervous system. We will continue to discuss the sympathetic nervous system and its functions in this lecture. We will explore the differences between the sympathetic and parasympathetic nervous systems. We will see how the sympathetic nervous system helps us to respond to stress or danger, and how it prepares the body for action. We will also discuss how the sympathetic nervous system is involved in regulating body temperature, and aiding in the digestion process. We will explore the role of the sympathetic nervous system in our daily lives, and how it helps us to respond to situations that require quick action. We will also see how the sympathetic nervous system is an essential component of our autonomic nervous system. We will continue to discuss the sympathetic nervous system and its functions in this lecture. We will explore the differences between the sympathetic and parasympathetic nervous systems. We will see how the sympathetic nervous system helps us to respond to stress or danger, and how it prepares the body for action. We will also discuss how the sympathetic nervous system is involved in regulating body temperature, and aiding in the digestion process. We will explore the role of the sympathetic nervous system in our daily lives, and how it helps us to respond to situations that require quick action. We will also see how the sympathetic nervous system is an essential component of our autonomic nervous system. We will.

[Audio] The sympathetic nervous system plays a crucial role in our body's response to stress and alarm situations. The cervical division of the sympathetic nervous system is responsible for innervating various structures in the head and neck region, including the eyes, glands, skin, and cerebral blood vessels. These structures are supplied by postganglionic fibers that originate from the superior cervical sympathetic ganglion. The sympathetic nervous system also has two types of fibers: cholinergic and vasodilator. Cholinergic fibers release acetylcholine, a neurotransmitter that stimulates muscle contraction, while vasodilator fibers cause blood vessels to dilate, leading to increased blood flow. The sympathetic tone refers to the overall level of activity of the sympathetic nervous system, which is essential for maintaining homeostasis and responding to changes in the environment. In terms of physiological importance, the sympathetic nervous system helps regulate heart rate, blood pressure, and body temperature. Additionally, it plays a key role in the "alarm response," which is characterized by increased alertness, arousal, and readiness to respond to threats or dangers. This response is mediated by the sympathetic nervous system, which releases hormones such as adrenaline and noradrenaline to prepare the body for action. Overall, the sympathetic nervous system is a vital component of our autonomic nervous system, and its functions are essential for maintaining our physical and emotional well-being..

[Audio] The sympathetic nervous system plays a crucial role in preparing the body for emergency situations, such as stress responses. This system is often referred to as the "fight or flight" response, where it mobilizes energy and prepares the body to either confront or flee from a threat. The sympathetic nervous system is responsible for increasing heart rate, blood pressure, and respiration, allowing the body to respond quickly to emergencies. Additionally, it stimulates the release of hormones like adrenaline, which helps to increase energy levels and enhance physical performance. In everyday life, the sympathetic nervous system also regulates various bodily functions, including exercise, digestion, and circulation. Its catabolic function enables the body to break down stored energy sources, such as glycogen, into glucose, providing a rapid source of energy. Furthermore, the sympathetic nervous system helps to regulate blood vessel diameter, causing them to constrict and redirect blood flow towards vital organs during times of stress. Overall, the sympathetic nervous system is essential for maintaining homeostasis and responding to changes in the environment. By understanding how this system works, we can better appreciate its critical role in our daily lives..

[Audio] The sympathetic nervous system originates from the lateral horn of the spinal cord at the level of T1 to L2 segments. This indicates that the sympathetic nervous system has its origin in the thoracolumbar region of the spinal cord. The term "Thoracolumbar outflow" is used to describe this specific area where these neurons are located. The origin of the sympathetic nervous system is crucial because it explains why the sympathetic nervous system is often referred to as the "Thoracolumbar outflow". In essence, the name reflects the location of the sympathetic preganglionic neurons, which are responsible for transmitting signals from the central nervous system to the peripheral nervous system. Understanding the origin of the sympathetic nervous system is essential for grasping its overall function and mechanisms. By recognizing the specific segment of the spinal cord where these neurons arise, we can better comprehend how the sympathetic nervous system regulates various bodily functions, such as heart rate, blood pressure, and body temperature. Furthermore, knowing the origin of the sympathetic nervous system allows us to appreciate the complex interplay between different neural systems and their roles in maintaining homeostasis..

ion Of spinal cord Associated nerves and prevertebral ganglia Medulla Right chain ganglia Skin Spinal cord Left chain ganglia Greate( s sa Coccygeal ganglia fused together (ganglion impar) Celiac ganglion Superior mesenteric ganglion Inferior mesenteric ganglion Target organs (effectors) Lacrinal gland Mucous membrane- nose and palate Submaxillary gland Sublingual gland Mucous membrane- Parotid gland Heart Larynx Trachea Bronchi Esophagus Stomach Abdominal blood vessels Liver and bile duct Adrenal gland Small intestine Large intestine Rectum Kidney Bladder External genitalia.

Superior, middle, inferior ce ga Cervical region (head & neck) boracic r ion T12 — Abdominal region Coeliac ganglion Superior mesenteric ganglion Lumber region Inferior mesenteric ganglion.

[Audio] The cervical division of the sympathetic nervous system has a significant impact on the regulation of bodily functions in the head and neck region. Preganglionic fibers originate from the lateral horn of the upper two thoracic spinal segments. These fibers then travel to the superior cervical sympathetic ganglion before reaching their final destination via postganglionic fibers that branch off the carotid arteries. The postganglionic fibers provide innervation to several key structures, including the eye, glands, skin, and cerebral blood vessels. This complex network enables the sympathetic nervous system to effectively regulate various physiological processes in the head and neck area..

[Audio] The cervical division of the sympathetic nervous system plays a crucial role in regulating various bodily functions, particularly those related to the head and neck region. This division originates from the lateral horn of the upper two thoracic spinal segments and relays information through the superior cervical sympathetic ganglion. The postganglionic fibers then branch off along the carotid arteries, supplying several key structures including the eyes, salivary glands, skin, and cerebral blood vessels. These functions enable the body to respond to stress and maintain homeostasis in the face of changes in the environment. Understanding the cervical division's role is essential for grasping the overall physiology of the sympathetic nervous system..

[Audio] The cervical division of the sympathetic nervous system plays a crucial role in regulating various bodily functions, particularly those related to the eyes. One of the key functions of this division is the inhibition of tear secretion, which helps to reduce excessive tearing during emotional responses such as crying. Additionally, the dilation of the pupils, known as mydriasis, allows for better far vision and enables individuals to see objects more clearly over long distances. Furthermore, the contraction of the superior and inferior tarsal muscles leads to a wider palpebral fissure, making it easier to open one's eyes wide. Finally, exophthalmos, or forward protrusion of the eyeball, occurs due to the contraction of these muscles. These effects collectively contribute to the overall functioning of the eyes and enable individuals to respond effectively to their environment. The cervical division of the sympathetic nervous system also has other functions, including regulating glandular secretions, controlling blood pressure, and influencing skin temperature. Understanding the role of the cervical division is essential for grasping the broader mechanisms of the autonomic nervous system..

[Audio] The dilation of the pupils, also known as mydriasis, occurs when the sympathetic nervous system is stimulated. This is achieved through the activation of the dilator pupillae muscle, which causes the pupils to widen. The dilator pupillae muscle is controlled by the sympathetic nervous system, specifically through the cervical division. When this muscle contracts, it leads to the dilation of the pupils, allowing for better far vision. Additionally, the contraction of the superior and inferior tarsal muscles results in a wider palpebral fissure, further contributing to improved far vision. Furthermore, the forward protrusion of the eyeball, known as exophthalmos, can occur due to the contraction of these muscles. These changes enable individuals to see objects more clearly over long distances..