Topic 7 Further Anatomy

7.1 The skin system

7.1.1 Annotate a diagram of the generalized structure of the skin. The skin covers the entire external surface of the human body and is the principal site of interaction with the surrounding world. Anatomy of the skin: Epidermis Dermis Fat (subcutaneous tissue) Integumentary glands (sweat glands, Sebaceous glands) Hair follicles.

7.1.1 Annotate a diagram of the generalized structure of the skin.

7.1.2 Describe the functions of the skin. 1. Regulation of body temperature   Evaporative cooling: In hot weather there is an increase in blood flow to the skin. There is an increase in sweat production by the sweat glands. Evaporation of sweat cools the skin which leads to a decrease in body temperature. Insulation via the sub cutaneous fat layer.

7.1.2 Describe the functions of the skin. 2. Protection and immunity Protection of underlying tissues against impact, abrasion, fluid loss, and harmful chemicals.

7.1.2 Describe the functions of the skin. 3. Sensation Detection of touch, pressure, pain and temperature stimuli through nerve endings and receptors in the skin. This information is relayed to the nervous system

7.1.2 Describe the functions of the skin. 4. Excretion Excretion of salts, water and organic wastes by integumentary glands.

7.1.2 Describe the functions of the skin. 5. Synthesis of vitamin D. When exposed to sunlight (ultraviolet radiation, UVB) epidermal cells produce vitamin D. Vitamin D is important in the absorption of calcium, which promotes bone growth and muscle contraction.

7.2 Structure and function of the brain

7.2.1 Label the location of the principal structures of the brain.

7.2.2 Label the location of the principal lobes of the cerebrum.

7.2.3 Outline blood supply to the brain. Blood supply to the brain comes from the aortic arch. Right side The Brachiocephalic trunk originates in the aorta and leads into the right carotid artery. This splits into the right internal carotid artery and right external carotid artery.

7.2.3 Outline blood supply to the brain Left side Left carotid artery originates from the aorta. This splits into the left internal carotid artery and left external carotid artery.

7.2.3 Outline blood supply to the brain The external carotid artery flows upward on the side of the head to branch into various structures in the neck, face, jaw, scalp, and base of the skull. The internal carotid artery enters the skull and supplies the anterior part of the brain (via cerebral branches), the eye and its appendages, and sends branches to the forehead and nose.

7.2.3 Outline blood supply to the brain The blood brain barrier Blood brain barrier is a network of blood vessels that allows the entry of essential nutrients into the brain while blocking other substances. The blood-brain barrier helps block harmful substances, such as toxins and bacteria from entering the brain. Compounds that are very small and/or fat-soluble, including antidepressants, anti-anxiety medications, alcohol, cocaine, and many hormones are able to slip through the endothelial cells that make up the blood-brain barrier without much effort. In contrast, larger molecules, such as glucose or insulin, must be ferried across by proteins. Parkinson’s disease/ altimerz disease can’t be treated with drugs due to the BBB not letting them cross from the blood into the brain.

7.2.4 Describe the principal source of energy for brain cells. The brain obtains energy using glucose and oxygen, which pass rapidly from the blood to the brain cells. Glucose and oxygen are used to make ATP inside the brain by the process of aerobic respiration. It consumes about 120 g daily, which corresponds to an energy input of about 420 kcal (1760 kJ) ≈ 8 apples

7.2.4 Describe the principal source of energy for brain cells. Carbohydrate storage in the brain is limited, so the supply of glucose must be continuous. If blood entering the brain has low glucose or oxygen levels, mental confusion, dizziness, convulsions, and loss of consciousness may occur.

7.2.5 Explain the function of the principal parts of the brain. Brain stem: The autonomic cardiovascular and respiratory control centers and found in the brain stem (medulla oblongata). Control of heart rate, blood pressure, breathing rate and breathing depth all occur in the brain stem. Chemoreceptors in the aorta detect changes in blood pH or a change in blood pressure.

7.2.5 Explain the function of the principal parts of the brain. The brain stem responses by changing heart rate and stroke volume for the cardiovascular system. It changes breathing rate and depth in the ventilatory system. Hormones like adrenaline can affect the cardiovascular centre and cause it to increase the rate of impulses sent to the heart, increasing heart rate and stroke volume.

7.2.5 Explain the function of the principal parts of the brain. Diencephalon The diencephalon consists of the thalamus and hypothalamus. Thalamus: perception of sensations (pain, temperature, touch) cognition, relays information to cerebrum

7.2.5 Explain the function of the principal parts of the brain. Hypothalamus: control of the autonomic nervous system adjusts and coordinates autonomic centers in the brain stem the regulate heart rate blood pressure regulates hormones released from the pituitary gland. appetite and thirst regulates body temperature fluid and electrolyte balance circadian rhythms

7.2.5 Explain the function of the principal parts of the brain. Cerebrum The cerebrum is responsible for high-level brain function such as thinking, language, emotion and motivation. The function is divided into 3 broad processes: 1. Sensory (receiving sensory impulses) 2. Association (interpreting and storing input, and initiating a response) 3. Motor (transmit ting impulses to effectors).

7.2.5 Explain the function of the principal parts of the brain. Although the lobes do not function independently, each lobe is associated with certain aspects of the following processes. Frontal lobe—many aspects of association such as reasoning and motivation, planning, emotions and problem-solving. Also contains the speech and movement motor areas. Parietal lobe—somatic sensory and motor areas linked to movement, body awareness, orientation and navigation.

7.2.5 Explain the function of the principal parts of the brain. Occipital lobe - visual sensory and association centre. Temporal lobe - auditory sensory and association area; many aspects of long-term and visual memory. Limbic lobe - concerned with association processes such as emotion, behaviour, motivation and long-term memory.

7.2.5 Explain the function of the principal parts of the brain. Cerebellum Helps to smooth and coordinate sequences of skeletal muscle contractions. Regulates posture and balance. Makes possible all skilled motor activities, from catching a ball to dancing.