Nucleus
• Contains genetic material – Necessary for cell reproduction – Regulates cellular production of proteins
• Each cell is “programmed” by the genes for the production of specific proteins – Allows the cell to carry out its function– Maintains cell homeostasis or stability– Promotes cell division
Cell Membrane• Structure
– Thin barrier that separates the intracellular fluid from the extracellular fluid
• Function– Essential for cellular integrity– Equipped with many mechanisms for
maintaining cell homeostasis
Features of the Cell Membrane• Specific receptor sites that allow interaction with
various chemicals
• Histocompatibility proteins that allow for self-identification
• Channels or pores that allow for the passage of substances into and out of the cell
Structures of the Cytoplasm• Mitochondria
• Endoplasmic reticulum
• Free ribosomes
• Golgi apparatus
• Lysosomes
Cell Properties
• Endocytosis – Involves incorporation of material into the cell– Pinocytosis and phagocytosis occur
• Exocytosis – Allows a cell to move a substance to the cell
membrane and secrete the substance outside the cell
– Hormones, neurotransmitters, and enzymes are excreted into the body by this process
Achieving Cell Homeostasis
• Passive transport – Happens without the expenditure of energy and
can occur across any semipermeable membrane– Occurs by diffusion, osmosis, and facilitated
diffusion• Active transport
– Energy-requiring process– Movement of particular substances against a
concentration gradient– Important in maintaining cell homeostasis
Diffusion vs. Osmosis• Diffusion
– Does not require energy
– The movement of solutes from a region of high concentration to a region of lower concentration across a concentration gradient
• Osmosis
– Does not require energy
– Movement of water from an area low in solutes to an area high in solutes
Phases of the Cell Cycle
• Interphase
• G0 phase: Resting phase
• G1 phase: Gathering phase
• S phase: Synthesizing phase
• G2 phase: Last substances needed for
division are collected and produced
• M phase: Actual cell division occurs, producing two identical daughter cells
The nucleus is called the control center for the cell because:
• A) It is the site of protein metabolism
• B) It contains the individual units of
inheritance, the genes
• C) The energy-rich ATP is made in the nucleus
• D) It participates in cell-to-cell recognition
Which of the following organelles contains powerful digestive enzymes that assist in
digesting intracellular materials?
• A) Golgi bodies
• B) Mitochondria
• C) Ribosomes
• D) Nucleoli
• E) Lysosomes
Types of Barrier Defenses
• Skin – Protects the internal tissues and organs of the
body
• Mucous membranes – Line the areas of the body that are exposed to
external influences but do not have skin protection
• Gastric acid– Secreted by the stomach in response to many
stimuli
• Major histocompatibility complex– Distinguishes between self-cells and foreign cells
Types of Cellular Defenses
• Mononuclear phagocyte system (MPS)– Composed of:
• Thymus gland• Lymphatic tissue• Leukocytes• Lymphocytes• Numerous chemical mediators
Description of a Typical Inflammatory Reaction
Heat– Caused by increased blood flow
Swelling– Caused by fluid that leaks into the tissues
Redness– Caused by the increase in blood flow due to
vasodilation
Pain– Caused by the activation of pain fibres
The Immune Response
• More specific responses to foreign agents stimulates a more specific immune response– Lymphocytes produced in the bone marrow can
develop into T lymphocytes or B lymphocytes
– Other identified lymphocytes include natural killer cells
• These cells are aggressive against cancer cells –– to promote rapid cellular death
Adaptive & Specific Immunity
Natural-PASSIVE maternal antibodies
Artificial- Passive, InjectedIMMUNOGLOBULINS
Natural -ACTIVE Infection
Artificial- ACTIVE VACCINATION
What are the self components that the immune system uses to distinguish
self from nonself?
• A. Antibodies
• B. Major histocompatibility molecules
• C. Cytokines
• D. Lymphocytes
Which one of the following is an example of Natural active
immunity?
• A) Protection against infections that is passed from mother to infant through the placenta
• B) Protection afforded after an infection
• C) Protection afforded against hepatitis by an injection of pooled gamma globulin
• D) Protection afforded to an infant from a mother’s breast milk
Autonomic Nervous System
• Definition– Involuntary or organ nervous system
• Function– Mostly with little conscious awareness of activity
– Regulates and integrates body internal functions
– Integrates parts of the CNS and PNS to react to changes in the internal and external environment
Functions Regulated by the ANS
• Blood pressure
• Heart rate
• Respiration
• Body temperature
• Water balance
• Urinary excretion
• Digestive functions
Composition of the Nervous System
• Central Nervous System (CNS)– Composed of the brain and spinal cord
• Peripheral Nervous System (PNS)– Sensory receptors bring information into the CNS– Motor nerves carry information away from the CNS
• Autonomic Nervous System (ANS)– Uses components of the CNS and PNS to regulate
automatic or unconscious responses to stimuli
Role of the Nervous System
• Controlling the functions of the human body
• Analyzing incoming stimuli
• Integrating internal and external responses
Types of Nerve Axons
• Afferent fibres – Nerve axons that run from peripheral receptors
into the CNS
• Efferent fibres– Nerve axons that carry nerve impulses from the
CNS to the periphery to stimulate muscles or glands
Examples of Neurotransmitters
• Acetylcholine– Communicates between nerves and muscles
• Norepinephrine and epinephrine – Catecholamines released by nerves in the
sympathetic branch of the ANS
Components of the Brain
• Hindbrain– Runs from the top of the spinal cord into the
midbrain; contains the brainstem– Controls basic, vital functions
• Midbrain – Contains the thalamus, the hypothalamus, and
the limbic system • The thalamus sends direct information into the
cerebrum to transfer sensations
Components of the Brain
• The hypothalamus acts as a major sensor for activities in the body
• The limbic system appears to be responsible for the expression of emotions
• Frontal Lobe – 2 cerebral hemispheres joined together by the
corpus callosum– Receives and sends nerve impulses,
coordinates speech and communication, and facilitates learning
Spinal Cord
• Made up of 31 pairs of spinal nerves– Each spinal nerve has two components or roots
• Sensory fibre (dorsal) – Brings information into the CNS from the periphery
• Motor fibre (ventral)– Causes movement or reaction
Functions of the Central Nervous System
• Sensory functions
• Motor functions
• Intellectual and emotional functions
Nodes of Ranvier are associated with nerve conduction in:
• A) unmyelinated axons
• B) astrocytes
• C) microglial cells
• D) ependymal cells
• E) myelinated axons
The brain region most closely associated with the control of
homeostasis is the
• A) diencephalon
• B) hypothalamus
• C) thalamus
• D) cerebral cortex
• E) basal ganglia
Nervous System & Endocrine System
• They work together to maintain internal homeostasis
• They integrate the body’s response to the external environment
Characteristics of All Hormones
• Produced in very small amounts
• Secreted directly into the bloodstream
• Travel through the blood to specific receptor sites
• Act to increase or decrease the normal metabolic processes of cells when they react with receptor sites
• Are immediately broken down
Hypothalamus
• Definition– “Master gland” of the neuro-endocrine system
• ActionConstantly monitors the body’s homeostasis by:
• Analyzing input from the periphery and the CNS• Coordinating responses through the autonomic,
endocrine, and nervous systems
Releasing Hormones Produced & Secreted by the Hypothalamus
• Growth hormone–releasing hormone (GHRH)
• Thyrotropin-releasing hormone (TRH)
• Gonadotropin-releasing hormone (GnRH)
• Corticotropin-releasing hormone (CRH)
• Prolactin-releasing hormone (PRH)
Hormones Produced by the Hypothalamus
• Antidiuretic hormone (ADH)
• Oxytocin– Stored in the posterior pituitary to be released
when stimulated by the hypothalamus
Connecting the Hypothalamus to the Pituitary Gland
• Vascular network carries the hypothalamic releasing factors directly into the anterior pituitary
• A neurological network delivers ADH and oxytocin to the posterior pituitary to be stored
Lobes of the Pituitary Gland• Anterior lobe
– Produces six major anterior pituitary hormones
• Posterior lobe– Stores two hormones
• Intermediate lobe– Produces endorphins and enkephalins
Major Anterior Pituitary Hormones
• Growth hormone (GH)
• Adrenocorticotropic hormone (ACTH)
• Follicle-stimulating hormone (FSH)
• Luteinizing hormone (LH)
• Prolactin (PRL)
• Thyroid-stimulating hormone (TSH, also called thyrotropin)
Other Hormones Released in Response to Stimuli
• Insulin, glucagon, and somatostatin • Parathormone• Erythropoietin and renin • GI hormones• Calcitonin• Prostaglandins • ACTH and the adrenocorticoid hormones• Aldosterone
A characteristic common to all hormones is that they:
• A) exert their effects by altering the rate of a body reaction
• B) are secreted at a uniform rate
• C) must be produced in large quantities to exert their effects
• D) always exert their actions at the site of secretion
Which of the following is NOT considered a tropic hormone?
• A) Adrenocorticotropic hormone (ACTH)
• B) Thyroid-stimulating hormone (TSH)
• C) Aldosterone
• D) Luteinizing hormone (LH)
Hormones Produced in the Ovaries
• Oestrogen– Oestradiol, Oestrone, and Oestriol– Enter cells and bind to receptors within the
cytoplasm – Promote protein synthesis
• Progesterone– Released into circulation after ovulation
Effects of Progesterone• Decreased uterine motility
• Development of secretory endometrium
• Thickened cervical mucus
• Breast growth
• Increased body temperature
• Increased appetite
Function of the Hypothalamus• Releases GnRH at puberty
• Stimulates the anterior pituitary release of FSH and LH
• Stimulates the production and release of the sex hormones
• Controls levels by a series of negative feedback systems
Components of the Testes• Seminiferous tubules
– Produce the sperm
• Interstitial (Leydig) cells– Produce the hormone testosterone
Production of Sperm in the Seminiferous Tubules
• In response to FSH stimulation, and testosterone in the interstitial cells
• In response to LH stimulation
Effects of Testosterone
• Growth of male and sexual accessory organs
• Growth of testes and scrotal sac
• Thickening of vocal cords
• Hair growth
• Increased protein anabolism and decreased protein catabolism
• Thickening of cartilage and skin
4 Phases of Human Sexual Response
• Period of stimulation with mild increases in sensitivity and beginning of stimulation of the SNS
• Plateau stage when stimulation levels off
• Climax resulting from massive sympathetic stimulation of the body
• Period of recovery or resolution
The function of the scrotum is to:
• A) produce sperm
• B) produce testosterone
• C) enclose and regulate the temperature of the testes
• D) transport sperm
All of the following are hormones related to the functioning of the male
reproductive system EXCEPT:
• A) luteinizing hormone
• B) follicle-stimulating hormone
• C) testosterone
• D) prolactin
The secretion of FSH and LH is under the direct control of:
• A) oestrogen
• B) thyroxin
• C) oxytocin
• D) gonadotropin-releasing factor
During the follicular stage of menstruation, increasing levels of what hormone exert a
negative feedback effect on FSH?
• A) Oestrogen
• B) Luteinizing hormone
• C) Progesterone
• D) Follicle-stimulating hormone
Components of the Nephron• Bowman’s capsule
• Ascending loop of Henle
• Distal convoluted tubule
• Collecting ducts
• Renal pelvises
Processes Involved in the Functioning of the Nephrons
• Glomerular filtration– Straining fluid into the nephron
• Tubular secretion – Actively removing components from the capillary
system and depositing them into the tubule
• Tubular reabsorption – Removing components from the tubule to return
them to the capillary system and circulation
Factors Stimulating Release of ADH
• Falling blood volume
• Sympathetic stimulation
• Rising sodium levels
Role of the Kidneys• Influence blood pressure control
• Release renin to activate the renin–angiotensin system
• Leads to increased blood pressure and volume
• Increased blood flow to the kidney
• Can lead to water retention or excretion
Male Urethra
• Passes through the prostate gland– May enlarge or become infected
• Often associated with advancing age
The functional unit of the kidney is the:
• A) nephron
• B) glomerulus
• C) the proximal tubule
• D) the ascending and descending limb of the loop of Henle
• E) the collecting duct